When you're doing stranded knitting, you don't want to work too tightly or have your 'floats' of yarn across the back to tight or you will get puckering.
The way I catch the long floats is this--it catches the yarn without twisting anything.
Insert your needle as if to make the next stitch. Bring your carried yarn up over the right tip from back to front. Make sure it comes up from under the working yarn. Wrap the stitch with your working yarn as normal, but before you pull it through to knit it, remove the yarn you laid over the top of the needle. It may take a few tries to get it, but it works really well.