Do you have any "must know" tips for a sewing newbie?

The last time I really sewed anything was 7th grade. I know how to thread a sewing maching and sew stuff, sorta. It always looks uneven….. I used to sew with my grandmother and have some experience with patterns, but the whole task feels a tad daunting. I want to make pillow cases for some couch pillows and I have already picked out fabric.

So any tips on how to begin? Essential items? I never had much experience shopping for the items since my grandmother grew up in depression era and stock piled everything. I spent hours digging throughout the lace, yarn, thread, and buttons. Mostly for crafty things, not necessarily just sewing. Now it’s time to create my own stash.

Thanks in advance!