Garr... ok, game and Watch.
Couple of things you need to know. First of all, the key hits twice, once in the air and once on the ground, so just be patient there if you shield it. Second of all, lightshield is pretty good in this matchup if you have to shield, it's a little easier for Yoshi if you can start out with some distance. Third, countering the manhole, well it's like trying to counter Yoshi's dtilt lol, you really just have to jump over it and SHFFL a sex kick or be all predicty and land a forward air on his head.
Anyway Game and Watch with good spacing/prediction is just hard to get in on. Avoid taking damage, obviously, so you can get in some DjCCs, which I think are pretty key in this matchup (lol key) to throwing the G+W off. If he thinks his aerials are no good, then what can he do?
At low %s, you can crouch the f-air, but not the downair, due to the ground hit and the manhole.
Otherwise I guess work on your pressure game. Things like DjC nair to Ftilt work great because of Game and Watch's crappy shield.