I was all set to suggest USPS " Priority" .......

There really isn' t a product that you can just slap on and expect more speed......Lobi already hit on some of the things.

1. More draw weight (If you are up to it and your bow has some room to grow)
2. Longer draw length (Ususally not an option)
3. Lighter arrows......can mean just lighter arrow components or heads.
4. Less string load (Lose any heavy silencers, peep tube excess brass nock sets...etc.)

That' s about it.