I usually wind up maxing out the whole werewolf perk tree. I initially focus on the right side of the tree first and the first perk of the tree to get the damage going (Bestial Strength). I do the totem perks last. I find the fear totem the most useful, which you start out with by default.
If you see your foe coming, give your character time to transform. After transformation, rush at one of the NPCs doing a sprinting forward power attack. That typically knocks them down and kills that one instantly. Then use the werewolf's roar to scare off the weaker NPCs, then do a normal forward power attack (not sprinting) to send the tougher ones flying (clawing uppercut). Rush in doing a sprinting forward power attack to finish off the tougher one right after sending them flying. Sprinting forward power attacks often are one shot kills.
You can do a triple melee combo by simply holding in your attack button while stationary. One melee combo I find quite useful at times: press attack, then press and hold attack for 2 seconds and finish with a forward power attack. Don't forget that werewolf melee works like dual wielding (left and right attack) but much more versatile.
Be wary of NPC's power attacks. Especially 2hander weapon NPCs. I find their power attacks stun your werewolf for a few seconds, making it seem like your attack and howl controls are not responding for those seconds.
If your werewolf is low on health, try to scare off the NPCs using the fear roar, giving you time to feed and recover some health.
If you have the Dragonborn DLC you can go to Frostmoon Crag and purchase the Ring of the Hunt from Majni. It regenerates your character's health while in werewolf form. Be sure to bring about 6000 septims with you
Edit: if your character uses light armour, invest in the Wind Walker perk. Wind Walker light armour perk paired with the Animal Vigor werewolf perk can help regenerate stamina at astounding rates. Lastly, if you think you're relatively done leveling your character, use the Lord Stone for the resistance benefits.