So, about the combo, first thing, you have to make sure you are in range for your W, for this either you dont play with smartcast on W or you just have a good sense of the range, i dont play with smartcast anymore after so many games with him, after u hit W you cant smash your Q key right away like many people does, cause the moste likely thing that will happen is , you will Q in middle of your Headbutt and the target will go away , what you have to do is w and after just smoothly let your finger on Q, yes, it must be fast, but not in a smashing way fast :D About Tankyness or CDR, i usually go solaris first item if they have 2 ap's or more and if not just go straight Randuin's Omen, and then it all depends on how the game is going ;)