few tips, main udyr. didn't do all that well last season, got up to 1400 though with a 60% win rate on Udyr at 75 ranked games:
If they have a blue dependent jungler who is not the best dueler:
Boots + pots
Start wraiths, leash on red, smite... run straight to blue, skipping wolves, kill using pots, get to red bush, will time it probably right as they start fighting. good chance your smite will be up by then. Can smite steal red and engage for gank.
Otherwise: Try to by wards and be hyper aggressive on the invade. I've been playing heavy on the blue steals at 7:20, which depending on your elo can be easy or not, and then just around like a crazy man-bear-tiger-phoenix-turtle destroyer.
Potential to start their red if your team is coordinated. can either lvl bear, go gank, then blue. but you'll be a bit low if you do this and fail. can also grab turtle, go blue, and just continue jungling.
General advice? Chase with phoenix up inbetween hits, let flames smoke em. Try not to initiate with bear right as you arrive, 1 second cd to phoenix. initiate bear a second out for faster switch. Udyr doesn't have gap close, if ganking lanes try to come from enemy jungle if possible.
If you can get an early lead you can be a menace in their jungle. abuse that.