THIS GUIDE WILL BE SHORT AND SWEET JUST LIKE YOUR LYCAN GAMES
In the jungle the mighty jungle, all that matters is mana and your wolves. Basi ring + 2 clarities off the break is indisputably the best choice. I usually go for a sage's mask as my first item because the mana regen is amazing, but it doesn't really matter. What matters is you get your vlads (i sometimes get medallion first if they don't look like they have any intention of harassing me in the woods). once you have level 4 wolves and a vlads you're good to do rosh at any time. I usually get a medallion first as it speeds up the procedure a lot (the less time you spend in rosh's pit the better).
You're now in the mid game and assuming they didn't have a ****head support chase you around with wards you should have vlads/medallion/treads and either return to your jungle to continue to farm until mid game or if you are a team player help push a lane. Lycan even this early into the game is a monster pusher with his wolves and suddenly having him lope into your lane and push you to your tower and all 3 dudes go to town on it will result in either forcing them to respond in mass or a tower kill.
Once again your choices are: farm jungle (or a lane if it is available) or go for more tower kills. Lycan isn't a late game hard carry so this mid game to early late game area is where you shine make sure you don't let it pass you by while you sit around in the jungle doing nothing.
The big items! BKB is great because it allows lycan to push towers with next to no fear of death because a lycan with bkb and his ult can't really be stopped by much other than channeled ulti-disables also because it is a bkb. Deso is beast because you can get it really fast, it makes you hit like a train and strips armor from towers for more push power. Basher is good because it is cheap as hell, gives good damage, and a stun in one of your hollywood chase scenes (you'll do this as people flee from your max movespeed wolf ult) is usually a kill (also it allows you to save an inventory slot by being able to transition into a lategame item). Necronom is only recommended if you know what you're doing. It gives decent stats, purges lycan of his mana problems completely and gives un-****ing-believable push power as well as invis detect at level 3. coupled with his howl **** lvl3 necronom + wolves + lycan could backdoor fort knox so fast the mission impossible theme song wouldn't even have time to start playing.
Don't be scared to scout with your wolves also, once you have vlads and a few levels killing creep doesn't hurt you, it is faster with your wolves but I mean they're invisible how imba is that? they're like little scouting machines.
Also remember to carry a TP, this isn't a lycan thing you just always should be carrying a tp on everybody always and don't buy a ******** hand of midas on lycan.