Hello out there. This may seem like a dumb question to some of you but to me it is a real headache.
How in the world does a person keep the circular needles from curling up when you are knitting?

That can be a problem. I have even introduced a twist in a piece because the needle was twisted. If you put the cable in really hot water for a few minutes before you start it seems to help. As you continue to work the weight of the work seems to stretch the twist out. The newer circular cables don't have so much memory and don't stay coiled so much. A couple of years ago someone started marketing a circular with a stretch cable, material something like a bungee cord but much smaller. I haven't seen anything about that lateley but it seems like a good idea

The needles you're using make a huge difference.
Some brands twist and curl worse than others.
Two brands that have thin, relaxed, non-curling cables are Addi and the Options needles from KnitPicks. The cables in the Denise interchangeable set are also quite soft even though they are thicker than some people prefer.

I've been phasing out the really stubborn ones (mostly Susan Bates). But the hot water treatment does help, especially if you pull the cables straight while they cool.

Thank you very much for the info. I will try the hot water method & go from there.

I find that a quick dunk in my cup of tea solves the problem mostly.