DACUS is hard to do especially with tap jump on, but it's pretty integral to sheik's game as a whole, especially the MK MU where you can air release -> DACUS him.
DACUS is pretty situational though, you can't DACUS against very campy characters because things like lasers and arrows get in the way of you being able to do it.
If you find another person to play with offline, give each other feedback on playstyle. Make sure it doesn't sound like either of you are trying to get their ego on lol, just make sure to note what they did right, and what they could improve on, and ask the same in return.
For example, I've been telling my friend who recently picked up marth to try to space more in front so that he doesn't have to use Marth's bair to cover from behind, and that let's him save it for a fresh tipper bair to kill me when edgeguarding. He's also been telling me I've been having a dsmash habit lately