avoid editing in h. 264. it's a difficult codec for your computer to edit with because it's quite complex to code/decode, thus labour intensive. try transcoding to something like apple prores 422 or dvchd pro. I just use apple prores 422 lt, but experiment with that to see whats best.
Ok well i figured out a way that works well for me. I change the clips to pro res, intermediate codec ect. in mpeg streamclip and import to FCP seems pretty simple but i had never tried it ha. Well thanks for the tips.