I still think that your confidence level will drop if you dont feel you look good enough, that is the main culprit.
You need to be fairly cut and lean, V-body, nice set of pecs and arms, which is fairly doable over a short period of time.
The bulk would be great as well, but I dont think it's all that important. You have to be fit and athletic looking. I ve seen a few guys who arent all that big, but have a gymnast body, i.e. wide back/lats, pecs, big triceps/shoulders, who look extremely pleasing with the shirt off, but once you put the clothes on....the effect is diminished.
When I was heavier I used to fill the clothes better and girls did notice me more, but now that I am lean and I have to show it off here in there- tighter shirt, etc.
But: plenty average looking guys seal the deal everyday. In other words you can get away being less physically attractive yet having tight game, while the other way around won't work.