What are some major tips you think could help out a player struggling to get better?

If you asked me, my first and foremost answer would be: find the playstyle that suits you. Some of us are better at reacting rather than acting. Some of us are good at wearing down the opponent with one combo until they win, while others are better at adapting to every situation and even thinking up combos on the spot to win. Then and only then after you've recognized your strengths and weaknesses do I think you can truly find the best character that can amplify your skills and resonate with your type of style.