First attempt at a build based around making your rend on Tiger be as potent as it can be! AD scales 170% when it comes to Tiger, so couldn't resist making a build around it.

As far as laning goes, you should be pretty defensive early game, unless you have a good or suitable laning partner. You can be extremely good at surprise attacks, switching between bear and tiger will be how you do most things in this build, but it excels at chase downs and surprise attacks, rather than charging head on.

Normally, you should bear into a fight, stun, switch to tiger, rend them, etc. Tiger is where the majority of your damage comes from, if not all. Phoenix should only really be used for farming, AoE, or jungling.

Constructive criticism is welcomed. Please no "this build sucks!", more "You could change X for Y"

Oh, and I don't play any other AD champs, and I've normally gone with a hybrid/AS/junging build for Udyr, so please tell me if there's any item that seems out of place!

May update as my experience changes.

I picked Ignite for obvious reasons, it should (in my opinion) go on any pure DPS based build, it can be the difference between a kill and not a kill way too many times to miss out on it.

The second one is a little more preference, I picked Ghost because I love it's versatility and how it too can secure kills, although since Udyr has an amazing speed boost in his Bear stance, it's not compulsory.

Another few options for the second slot could be either Teleport or Exhaust, most of the time these depend on your team and preferences, but I'd recommend Ghost for it's pure versatility and it's ability to secure kills, and get that Bear stun off so your team can catch up!

Although I picked up a Sword of the Occult, if you are new to Udyr or aren't feeling too confident, I'd advise you to pick something different, like maybe starting with a Phage instead, or a Brutalizer for some ArP and a good CD reduction. The health pot is essential for starting off, 200 health early game is quite a lot.

Boots come later in the build as opposed to earlier due to Udyr's bear stance being all of the speed you'll need for most of the match, but obviously, move speed is highly important and shouldn't just be ignored. Berserker's boots may be considered, but that late in the game, your cooldowns will be more important, and with a Black Cleaver and your active Tiger up, you'll have 2.1 attacks/second anyway.

Trinity Force gives you a slight bit of bulk, an awesome improved Sheen effect, some attack damage, a slow, and loads of things which mean you shouldn't miss out on it, although it can be costly, it's more than worth the money.

The other items are kind of self explanatory, mostly just for the sheer AD they provide or something.