First (and most important) place to start is setting the bow to it's factory specs. Axle to axle length, brace height and(if dual cam)tiller.
Then cam timing or sync. This is done by twisting strings and cables to their correct lengths. If the string and cables are of decent quality they will pretty much be seated after a few dozen shots. If anyone tells you a cam and a half doesn't need timed, kick 'em in the nads and walk out the door!
Next, paper tune to determine arrow spine, center shot, contact, form, etc.
At this point (if done correctly) your bow will be shooting decent. This stage shooter ability comes in to play. Half to most will be shooting better than they ever had. But for some (picky Guys like me) micro or group tuning begins. Small (very small) adjustments to center shot, poundage and nock height will bring quality built broadheads and field points together.
Micro or group tune: Place a one foot cross + on your target ( if using duct tape tear in half lengthwise) aim at the edge of the tape and shoot at 30 yards. Shoot in only one plane (Dont try to shoot a group! I usually start with vertical) 6 arrows and see which side of the tape edge arrows impact. Move rest accordingly (left or right) to bring this impact in vertical line. Then do the same in horizontal plane. Correct by moving nock point (or rest if movable in this plane) up or down. When arrows are impacting the tape in both planes shoot for group. There is also a bare shaft tuning method. It can be a big can of worms for someone less experienced so try this one first.
This all sounds kinda complicated but it's really not. Any pro shop mechanic worth his salt will be able to easily put your bow in spec, get you paper tuned and if they have a range help you micro tune. If they dont have a range (like I said it's not rocket science) you can micro/group tune yourself.
