I saw the match against ROB.
First off, you need to abuse bair. It's G&W's best approach and you were using way too many fairs. Fair is too laggy. ROB also doesn't have many good options against bair OoS, as long as you space it.
You also rolled. As G&W, you never roll. His roll is slow, laggy and short. Complete crap.
Try to get ROB off the ground more and keep him in the air. Uair and nair handle ROB pretty well.
Another big problem, you didn't bucket brake. Super easy to learn, and super effective. It makes you survive to much longer percents.
Don't try to use your smashes to hard. If you want to hit a good opponent with them then you need to apply a constant pressure game and space your smashes correctly. Throwing them out randomly won't hit good opponents.
When you get a dthrow, ROB is too heavy to follow up with dsmash. That only works on light characters that don't tech. Instead follow up with a regrab or an usmash.
A lot of the time, you get near ROB, and do nothing. When you're that close to your opponent, you should be doing an aerial, airdodging, something so that you're not open.
Overall, not a bad G&W, you just need some more work on the basics.