Don't use drape frames if the item is in the A-pose rather than the T-pose. A lot of vendors are now using the A-pose (which I hate) rather than the T-pose. I think because DAZ Studio uses the A-pose. Anyway, Poser drape frames assume you're starting from the T-pose. You can still use the item without drape frames.

If that's not the issue, try adding some constrained vertices. Put them in places where cloth would be naturally constrained. For example, at the waistband if it's a skirt. The straps or the neckline of a dress.

Parenting the clothing to the figure might help as well. A shirt to the chest, pants or skirts to the hip.