well, keep in mind that if you are playing a good GW, you have to take advantage of him in neutral. if he gets you into a combo situation, you are going to eat a lot of damage and die relatively quickly. GW has some good approach options, between bair, dash attack, SHDB, spacing things like dtilt, dash attack, and his DACUS. however, GW does lack in the mobility and speed department. the properties of his approaches are good, especially on shield, but its the SPEED of the approaches that makes his neutral game suffer a bit. baiting with DDs to force reactions can allow you to punish him relatively effectively, depending on your character.
who are you using btw? its very MU dependent, but beating GW consists of making use of either superior mobility options or range. since his pressure game is limited, you have a lot of room in neutral to work with if you can supply better pressure than he can. its not too difficult to bait his up b OOS either.