Typical integrals:

ExampleBox
Substitution
Here y = x5 − x.
Integration by parts
Integration by parts
Substitution
Here y = sin(x).
It also fits the box "trigonometric integrals", but there the recommendation there is exactly the substitution as above.
Rational function (partial fractions decomposition)
Rational function (partial fractions decomposition)
Better: Substitution (numerator is the derivative of denominator).
Integration by parts
Substitution
Here y = ln(x).
Rational function (partial fractions decomposition)
Integration by parts
Integration by parts
Trigonometric integral
Either the universal substitution y = tan(x/2), or in this case also the easier y = tan(x).
Integral with a root of a quadratic
General method: indirect substitution x = 4sin(t).
Here we have a simpler alternative: Factoring out the constant leads to an elementary integral.
Rational function
Completing the square and factoring out a constant leads to an elementary integral

A well-prepared student should make such associations on the fly. Note that although the list is by no means exhaustive, experience suggests that if a student is really familiar with integrals of the listed types, he should do well on most integration problems.