String and pointy sticks are all you really need.
I do keep several other handy items in my bag that I've found useful over the years. Eventually I'm sure you'll reach a point where you'll want some of them, or items like them, though they aren't necessary by a long shot.
Small folding scissors, large blunt yarn needles, small retractable ruler for measuring the length of the project or gauge, a crochet hook for quickly picking up dropped stitches, small plastic rings for stitch markers, safety pins for marking my work (to mark an increase row, or to mark every 10th row so I can keep count when the number of rows is important). A small notebook and retractable pen are pretty handy too--i often get ideas, see a color pattern on a sweater, or make a small change in the pattern I'm following and want to remember it later.
I put the small loose stuff in pill bottles--keeps them tidy and I can see through the side of the bottle to see what's inside, no need to label anything.