A summary of the factors that determine initial Kinetic Energy...

There are exactly no more and no less than 2 factors that determine the amount of initial KE. They are: 1) The amount of biochemical energy the archer is able to transfer to mechanical energy stored in the bow limbs. This is bascially a fucntion of how strong the archer is but it is also influenced to a lesser degree by the ergonomic design of the bow. 2) The amount of stored mechanical energy the bow transfers to the arrow on release which is called efficiency. The higher the efficiency the more initial KE. Efficiency is effected by 2 factors. 1) The internal resistance the bow has to acceleration which is summed up in a term called virtual mass. Virtual mass is basically frictional resistance called dynamic hysterisis plus the resistance to acceleration due to the need to also accelerate the mass of the moving parts in the bow during launch which of course drains potential KE from the arrow. Virtual mass for a modern bow is typically around 100 grains. If you would like a better explination of virtual mass see http://homepage.ntlworld.com/joetapley/. The second and stonger factor effecting efficiency is arrow mass. The heavier the arrow the more efficient the bow transfers its mechincal energy, the lighter the arrow the less efficient.

To sum up, if you want more initial KE then you must transfer more biochemical energy to the bow, lower the bows virtual mass, or shoot a heavier arrow. There are no other options.

So "what is the best way to get kinetic energy?"

I don't know about best, best is somewhat subjective but think about this. Shooting more weight and shooting heavier arrows both have some downside associated with them. If you increase your weight too much it may negatively effect your ability to shoot accurately. Too heavy an arrow will produce a larger arch in trajectory making it more critical to judge distance accurately. The only factor that is "free" so to speak is to keep virtual mass as low as you can. If you use string silencers, choose the lightest you can that still do the job. If their are lubrication needs for your bow be sure its done regualarly. Use string knocs that are as light as possible. Also if you have things that are vibrating and/or making noise try to eliminate it. Doing this things won't make a huge difference but hey its free KE.