I have been knitting for years and trust me, it gets better. I still make mistakes (most recently, ripped out 5 hours of work because I tried to decrease in front of the TV. BAD IDEA). You will learn what method works and what doesn't. Find a book that speaks to you, whether that's one with pictures or one with words and go from there. Start small and finish those projects before moving onto bigger ones that'll let you down when they aren't finished.
To prevent stockinette from rolling, try a garter pattern or even ribbing depending on the piece. I have a few books that show me all different stitches and I love to pick one with some really pretty yarn and knit up a scarf for my family.
Trust me, it does get easier and you will get the hang of it! The best way to learn from your mistakes is to make them!