i need to use a clip, shot at 30 fps, in a 24 fps project. what's the best way to do this?  thanks.

you get it into the project at the original 30 fps framerate.

Avid will automatically apply timewarp on the clip if you cut it into the timeline.

you can the edit the timewarp, turn it to 100% speed to play every frame without jitter. This will give you slight slow motion and youll loose sound-sync, but the picture is clear.

if the picture needs to be sync with the sound, then you can only try different algorithms for the timewarp. Fluid motion might give very good results if you're lucky, depending on the picture.