Here's a tip I'll bet no one's ever heard of.
My mom, who's an award winning seamstress from 7th grade....well, i asked her about a problem i had . Here's the story: I bought a gorgeous pair of leggings, exceptional quality, from a consignment store. Waist a bit too big, and too much flare on bottom of leg. So i took in the waist, put new elastic in, no prob. But my darn New Home sewing machine wouldn't get that seam going. Kept skipping badly! I tried diff. settings (can't find my book!), bought a ball point needle, and finally asked mom for any other ideas?
Get this? Waxed paper. Yep. worked like a charm. Laid that stuff in 3" strips over where i was sewing and it grabbed like a charm. I never understood this very well, but it saved me $50 on a new pair of UnderArmour and i'm HAPPY! (btw, tore off waxed paper when done - lol)