'Farming' is the term used to describe the actions undertaken by a player with the goal being the acquisition of gold. It is most commonly used to describe a hero that is killing jungle or lane creeps, however the role of a ganker can be described as 'Farming heroes' as that is their main form of gold gain. Farming is most often done by core heroes, but also other roles to a lesser extent. Despite this it is important to consistently farm throughout a game of Dota 2.
Requirements for farming
Often in the earlier phases of the game, an effective jungling ability is needed to sustainably kill jungle creeps, for example Lifestealer's Feast or Enigma's Demonic Conversion, but when laning, no specific criteria is needed for a hero to effectively farm lane creeps. The same mostly applies in the late-game to jungling also, meaning cores can often sustainably kill jungle creeps as they have high enough health regeneration and health.
Carries such as Anti-Mage or Medusa who have 'farming mechanisms' to aid them (Anti-Mage has blink to maneuver around the map and Medusa has Split Shot to quickly kill multiple creeps). However, some supports also have abilities that allow them to farm jungle creeps, for example Crystal Maiden or Witch Doctor with Frostbite and Paralysing Cask respectively.
Core players will often use farming patterns to allow them to farm areas of the map efficiently. Consider loosely using a farming pattern when playing a core, as well as keeping track of the enemy core's movements for successful ganks. As a core you need to keep a balance of farming and fighting, so do not stick too strictly to a pattern as it will be too predictable and may leave you too far away from your team to help them if you do not have a Town Portal Scroll.
Consider whether you or anyone on your team should buy a 'farming item'. These items allow a hero to more effectively farm creeps if their skillset does not allow them to do so quickly enough to stay relevant in the game. Often these items may slightly hinder the effectiveness of the hero earlier in the game, so be mindful of that. If you are the carry, be sure to play more passively if you go for a farming item that potentially hinders your power. If you are against a player that opts for a farming item, take it as a cue to be more aggressive. With that item they will be able to gain an advantage later on, so you have to exploit their temporary weakness (due to not buying combat items) to delay them enough to win the game, or counter their hero in some way.
This is a method of neutral camp farming that involves leading neutral creeps out of their camps during the neutral camp spawn time to allow for another set of creeps to spawn. This method allows heroes with cleave or another form of farm acceleration to greatly increase the amount of gold they can obtain by killing many more creeps than they could without stacking. If a support has sufficient time and isn't required for more immediate tasks they can stack camps for their carry and allow a core with a farming skill to get items faster. Keep in mind if you don't have vision of these camps an enemy hero may be able to farm these camps without fear, effectively turning your work against you. If you have a sufficiently farmed carry you should consider stacking the ancient camp as it will provide them with a very large gold bonus. Use of a dominated Helm of the Dominator creep can allow a carry to stack camps by himself while continuing farm elsewhere, however this requires sufficient understanding of micro and a good memory to be effective.
During the early stages of the game, it is important to quickly figure out which farming item you should buy (if any) depending on how well you think your laning phase will go, whether you are able to out-carry opponents in the late game and whether the game will actually reach the point at which you will out-carry your opponents along with many other factors. However, you may need to change your choice of farming item if the game is turning out differently to your expectations. For example, Anti-Mage is likely to opt for a Battle Fury if his lane is going well and he is able to get an advantage over an opposing carry, allowing him to overpower them. However, if he needs to fight earlier on in the game to finish quickly and does not have a good laning phase, it is viable to go for more mid-game orientated items such as Drum of Endurance and/or Ring of Aquila over a farming item.
- Generally, Battle Fury is bought by melee core heroes that are able to take advantage of the farming speed it provides (and often possess a skill that synergizes with cleave such as Ember Spirit's Sleight of Fist), as well as the regeneration of mana and health. Examples are Anti-Mage and Ember Spirit. However, many other heroes can make use of these traits and players should not be afraid to purchase this item on unconventional heroes if it suites the situation of the game. Many melee hard carries should consider rushing this item if they have access to a lane where they can free farm as it will greatly accelerate their farm if it is gotten quickly. This item is most effective if you pull creep camps to get multiple stacks of creeps, as there is no limitation to the number of creeps that you can cleave within the radius. Keep in mind that outside of the bonus damage this will provide no farm acceleration for ranged hero.
- Maelstrom is an item that is usually used by core heroes with some way of sustainably farming already (long range, inert tankiness) and would like to increase that speed as well as not hinder their fighting power. It is the most expensive of the items in the above list when upgraded to Mjollnir because it is not only good for farming but fighting too. Sniper and Faceless Void both fit this criteria and benefit greatly from the item, along with many other heroes. Keep in mind if you are reliant on lifesteal or another attack modifier for successful farming this item will be of little use, it is also less effective than radiance and battlefury when dealing with large stacks of enemies due to the limited number of bounces. This item is also less effective at farming Mud Golems, and most ancient creeps as they are immune to magic damage.
- If a core (or even support in some cases) is in need of a level advantage to be powerful and have a very easy lane, a Hand of Midas is likely to be the choice. If buying this as a core you usually want to be a hero that is able to use the attack speed effectively, but are more level-dependent than gold-dependent. Examples of heroes that fit this criteria are Invoker or Doom. However, it can also be purchased on supports that have good attribute gains and highly scaling abilities, therefore appreciating extra levels such as Ancient Apparition. While the experience benefits of this item are immediate this item will not pay for itself for a substantial amount of time, therefore the earlier you can get it the more value it will give. This leads to some players "rushing" this item, or building this item as their first major item outside of basics purchased at the beginning of the game.
- Mask of Madness is usually an item for heroes without a Unique Attack Modifier as a skill or core item that need to be able to deal high DPS early in the game with basic attacks while also improving farming speed and sustainability. It also helps if the hero is someone who is at the back of a fight or has a big disable so they are not hindered by the 30% damage amplification too severely. Sniper and Faceless Void are good examples again and fit this criteria well. Keep in mind this attack speed bonus will also allow you to jungle more effectively, with the lifesteal more or less mitigating the damage amplication. If you are looking to gain quick jungling farm on a hero that would generally build lifesteal this may be your best option. A good example of a hero that could use this item for more efficient jungling is Juggernaut or Faceless Void.
- A Manta Style is mostly for heroes that have good spells or attributes which transfer to illusions and/or already have an illusion-summoning spell. It is often bought in combination with Radiance to allow the player to farm multiple areas of the map as the burn damage effect is given to illusions, or Diffusal Blade to allow for mana burning and increase fighting potential greatly along with farming. Heroes such as Naga Siren or Anti-Mage pick up this item. This item also allows for multiple-camp stacking simultaneously if the player has sufficient micro skills.
- As previously mentioned, Radiance is arguably the most effective farming item in combination with Manta Style. Radiance is usually bought by illusion-based heroes that have reasonable attributes without other items, or tanky heroes that are snowballing but lack AoE for fights. It is the most versatile in a sense too, since it deals consistent damage within a larger radius than Battle Fury and doesn't work on high attack speed to get procs like Maelstrom, meaning ranged or melee core heroes can buy it and get reasonable use out of it. Anyone from Enigma to Spectre to Bristleback can make reasonable use of this item. Its main downside is that the damage you receive from it is highly inefficient, and a lot of heroes need other items early instead. This is another item that can be "rushed", however due to its bulky main component Sacred Relic it generally requires a lane where the hero has little-to-no competition for last hits, or "free farm". Also keep in mind that this item is less effective if you are dealing with ancient stacks as Radiance burn does not affect most ancient creeps.