First of all make sure you pick up all of the starting items especially the health potions. These will help you stay in the jungle longer. This paired with Warwick's passive life steal and 'Q' will allow you to farm longer than most if not all champions on your first outing. For your first back try to have enough gold for the skirmishers sabre and berserker graves(1850). If you have any extra gold pick up a vision ward and put it in the enemy jungle, use this to steal farm form the opposing jungler and get ahead in levels and gold.

I focus on Warwick's 'Q' and 'W' to start with and then put one level in the 'E' so that when you do start ganking you can secure the kill with the increased movement speed. WHEN JUNGLING USE 'Q' and 'W' to lose as little health as possible. When kill monsters in groups always 'Q' on the monster with the most health to get the most out of the ability. In short 'Q' and 'W' are high priority 'E' is not but pick up your 'R' whenever you can.