As warwick, If Warwick invades you early, just back off. This is especially true if he is ahead, as you will not win early fights with him.

Be proactive with your Ultimate, as they will look to use theirs whenever it is up. Force ganks with your R!

As they will be ganking often in the early game, you need to make sure that you are also looking to gank as often as you can and abuse your E.

Focus on securing those objectives. You must take Rift Heralds and Drakes whenever you can! As warwick, If Warwick invades you early, right back. It's especially true if it's early, because you won't win early fights with it. Be proactive with your Ultimate, because they will seek to use theirs every time it's up. Force ganks with your R! As they will often gaunt in early play, you need to make sure that you also look at gank as often as you can and abuse your E. Focus on securing these goals. You need to take Rift Heralds and Drakes when you can!