Use wolves at the beginning of the laning stage to ease the process of last-hitting and denying. Make sure to use them throughout the game to scout your opponents and split push lane.
Howl is a powerful fighting ability, which you can also use to destroy structures or kill Roshan faster.
Level 4 Feral Impulse gives an insane 50% damage increase for Lycan and all his units. Its HP regen helps Lycan to sustain the laning stage comfortably.
This is the ability, on which all your gameplay should be based on. Whenever Shapeshift is ready to use, make sure to make something useful around the map. Apply pressure on Towers, make kills, kill Roshan and so on.
STARTING ITEMS carry
Make sure to buy enough healing items to sustain the laning stage comfortably.
EARLY GAME
Necronomicon is a key item to get on Lycan. It will significantly improve your pushing, farming and killing potential.
MID GAME
Assault Cuirass is an overall great item for Lycan. It improves his defensive potential and strengthten his ability to destroy structures even faster.
LATE GAME
Desolator is a very powerful pushing tool. In combination with Assaul Cuirass and all the units you will be able to demolush enemy base in a space of few seconds.
Nullifier will help you to basically hold enemy heroes in place and demolish them with the help of your units. This item is very effective against Pugna and Necrophos and is a powerful counter to Black King Bar.
SITUATIONAL
Aghanim's is a great item to get on Lycan as your second or third slot. Wolves will force enemy team to pay a lot of their attention to split pushing.
Satanic can help you to man-up and fight even strongest damage dealers in the game, such as Sven.
This relatively cheap item will significantly improve your push and single kill potential. Its cheap components can be very useful during the laning stage.
Decent item to get on Lycan versus very strong physical damage dealers, such as Sven or Ursa.
In various games you can try to skip the default build with units and go for Armlet. This is a decent option in games versus Enchantress and Chen.
Lycan is a hero, who wants to run freely in fights. In case your opponents have any annoying disables, it is absolutely necessary to get yourself a Black King Bar.
You can use Boots of Travel to teleport on your invisible wolves. It can help you to get an important kill or to quickly destroy the enemy base.
Monkey King Bar is necessary to buy in case enemy heroes have any powerful source of Evasion.
Mjollnir will help you to deal with illusion based heroes, such as Phantom Lancer or Naga Siren.
Power Treads can be useful to buy after you finish either HotD or lvl1 Necro. Lycan lacks attack speed, so PT is always a good option for him.
Bloodthorn is very powerful in combination with Nullifier. It will significantly improve your damage output.
Great alternative to Nullifier. Active stun in combination with passive bash will help you to hold enemy heroes in place and kill them without any problems.
Unlike Abyssal Blade and Nullifier, this item allows you to disable your opponents instantly from a longer distance. This item can be very effective against mobile heroes with escape mechanics.
Even though you don't really want to go for Linken's on Lycan, it can be essential to buy it if you play against a powerful single-target abilities, such as Flaming Lasso or Duel.
