Top-rope the Climb
Top-roping the route a few times will give you a strong mental picture of where the safest clipping stances and sensible places for the bolts are.
Place the First Bolt High Enough
To avoid groundfall, the first bolt should be placed high enough so that a climber will not hit the ground if he or she falls. If the first bolt is only a few feet off the ground, it won't do much good.
Have Consideration for Other Climbers
Set the bolts so that they are comfortable to reach for both short and tall climbers. A bolt may be easy to reach for someone 6 feet tall, but shorter climbers may struggle to make that same clip.
Make Comfortable Clipping Stances
Place bolts where you are comfortable making clips and you can rest and regain strength. Placing a bolt in the middle of a crux makes the climb difficult and can ruin the natural flow of the route.
Place Bolts Before a Crux
Protecting the crux is essential. Make a habit of placing bolts just before a difficult section where falls are likely.
Place bolts far enough away from obstacles like sharp protruding rocks or ledges. Keeping bolts far above dangerous rocks and ledges will prevent climbers from hitting them if they fall.