There are some very basic rules to cloth sim in Poser, and most were covered by the very experienced users above. In summary, I had success with the following:

1. ALWAYS start from zero pose. Do not apply a pose in Frame one, ever, just to be sure.
2. I usually add the character morphs in frame 5 so there is time to adjust and stretch.
3. I set sims to run for 30 frames. Apply the pose in Frame 30 (or however long you are running the sim).
4. Always check that there is no 'intersect' ie. no 'clothing part is inside the figure' in FRAME 1. If there is, move the clothing until there is no intersection (x,y,z or scaling).
5. With tight clothes, no draping, so uncheck that and like it was said above, also uncheck start draping from zero pose.
6. Don't mess with cloth settings just yet, the advice from AmethystPendant above about friction etc. is super good however. Also their advice about how to set the chair--I need to try that, wow.
7. Save once it's done; always render from Frame 30.
8. If you clothify a hybrid piece of clothing, make sure you don't add movement morphs like 'sit'. You are simming that with the dynamics.

It still will take a few tries. I can see why people are so rarely use dynamics because it may take just one little mistake to have the whole thing messed up and discouraging users. I really long for an easier system and dforce is a huge positive for the other company/software in that direction--undoubtedly this is another factor in why Poser really needs a thourough modernization.