To factor a quadratic of the form $x^{2} + bx+ c$, look for two real numbers $p$ and $q$ satisfying $p+q=b$ and $pq=c$.
To factor a quadratic of the form $ax^{2} + bx + c$ where $a \neq 0$ and $a\neq1$ quickly, use the guess and check method illustrated in the video.
To factor a difference of squares, use conjugate pairs: $x^{2} - p^{2} = (x+p)(x-p)$. A sum of two squares does not factor over the real numbers.
To factor a sum or difference of cubes, use the factoring formulas below. The trinomial you obtain by factoring a sum or difference of cubes does not factor further.
$x^{3} + p^{3} = (x+p)(x^{2}-px+p^{2})$
$x^{3} - p^{3} = (x-p)(x^{2}+px+p^{2})$
More techniques for factoring general polynomial functions are given in Chapter 3.
Common factoring. Factoring quadratics, part 1. Factoring quadratics, part 2. Factoring difference of squares. Factoring difference of cubes.