You will want to use the size needle that is appropriate for your thread. I found that I got shredding if I didn't use a topstitch needle, which has a larger eyehole and longer scarf. But the size is dependent on your thread - for instance, King Tut is a heavier thread, Bottom Line is a finer thread, so you would adjust the size of your needle accordingly.
A few tips:
If you get skipped stitches, go up one size larger needle. 99% of the time this solves my problem.
Tension issues on the bottom of the quilt are related to the top thread.
Tension issues on the top of the quilt are related to the bobbin thread.
Never EVER be afraid of asking questions. Even if you think it sounds stupid, most of the people will respond that they've done the exact same thing and we have a club.
Quilters are for the most part nice people and love to encourage newbies.