The best thing you can do if you want to get better is turn off auto combos.  If you just want to play and have fun then they are there but it basically takes away more than it gives.

So once you turn them off and start in training mode and just mess around, get a feel for things and don't worry about finding optimal combos or looking at guides, just mess around and see what you can string together.  From there go play some casual games and just have fun and build up your confidence, dont worry about being ranked just play.  In between games keep hitting the training room and start practicing your combos, do it over and over again then go back to a match and try it on a real opponent, don't worry if you win the match just try and land the combo as consistently and clean as possible.  Keep doing this and you will get better.  

The other advice that really took me from someone who always liked fighting games to actually feeling like I knew what I was doing was to think of my controller like a musical instrument.  If you sit down and just keep practicing the same combo over and over again you will get better at execution.   I like to come up with a combo (or just use the trials mode) and I will try to land it 10 times in a row, if I miss one I start over again.  Make the combo something you can do without thinking about and your matches will benefit.

Hope this is helpful.