I feel like people might disagree with me here but don't play Warwick or Yi neither of them will give you a true feel of how the jungle is meant to be played or what you can actually do. Malphite, Maokai, Amumu, Gragas, Sion would all be better champs to learn jungle with. They're tanky, they can gank pretty well and they initiate fights.

Maokai specifically is probably the best jungler to learn in my opinion. He's simple enough to grasp but still has complex capabilities people don't respect.

This is typically the jungle clear I go: Start Gromp, smite it -> Blue -> Wolves -> Red, smite it -> look for gank/raptors/double krug/river scuttle depending on stuff.

Gromp, Wolves, Raptors are all okay to smite. Never smite raptors and only smite Krugs if that's where you start your jungle route. Never smite the scuttle unless you're afraid the enemy will steal it from you.

You can smite the blue buff only if you need the mana, there's not point to smite it otherwise. In my opinion the krugs and blue buff are the worst camps to smite as they give you very little.

When to gank: When the enemy pushes up and are an actual gankable champion/your laner(s) can actually help you. For instance, if the ally laner is low don't gank and force them into that situation. If the enemy laner is low but they have an escape like LeBlanc for instance, don't bother because she will just be gone before you can do shit. If your ally has extreme amount of engage/CC like Thresh, Nautilus, Maokai, they're good lanes to gank as you will almost ensure you lock the enemy down enough to at least fight but make sure you have the damage for it. Ganking a tank top lane as a tank is usually pretty low damage and might not result in a kill. If you see your mid/top or support roaming to another lane, join them you can usually force fights with that many allies.

I dunno that's all I can think of.