Set: Permanent deflection of the limbs toward the archer, resulting from compression of belly wood beyond its elastic limit. Set and string follow are not the same..
String Follow: Where by set, design, or deflex in the stave, an unbraced bow’s tips rest some distance bellyward of the back. Usually the result of set.
The first step is knowing the difference between set and string follow. Keeping these straight in you head is the hardest part of the whole endeavour. With a little reflex to start it is possible to prevent string follow, but it is impossible to eliminate set.
Like mentioned before, tillering is huge. However, one of the biggest concerns is asking too little wood to do to much work. Too short or too narrow and you will have a problem. You will often hear about a minimum length safe for a bow design, but you cannot forget a minimum width. It is a fine balancing act.