You can think of factoring in terms of using the area of a rectangle to find the side lengths. If the area is a trinomial, start with a 2 x 2 box, and we know the first term must go in the upper left, and the third term must go in the bottom right. From there, you'll need to guess and check the outside values that would let your remaining diagonal boxes sum to the "b" term. The length and width that you discover represent the factors of the trinomial. This requires a lot of persistence and you'll get better with practice- don't quit!