The style of the garment is not as important as the quality of the pattern, but that can be hard to ascertain (even with lots of experience) until you knit it!

A simple sweater is likely to involve just a few extra stitch types like increases and decreases, and some new techniques, like knitting in the round, picking up stitches, or neck shaping. All of these are quite simple in principle, and should be reasonably easy to get the hang of.

How these steps are described is a whole other story! I recently helped a friend with a very simple vest, but it was honestly one of the most confusing patterns I've ever read. And I've knit hundreds of things over 20 years!

So my advice is:

1. Stick with patterns with good reviews, written by a quality pattern maker, or at least is very popular (more chance any kinks have been worked out)

2. Read through the whole pattern before you begin and see if it makes sense.

3. Ask an experienced knitter if you get stuck! There's a good chance the problem isn't your skills but the pattern itself.

What's the pattern? I'd be happy to take a look and give my two cents.