Which method to use for integration? A Level

Are there particular shortcuts to identifying what method to use for common types of questions?
For example when do I know I should use a substitution, by parts, reverse chain rule, or trig identity?
Thanks in advance!

The last page in
https://www.drfrostmaths.com/uploads/JFrost/files/C4CheatSheet.pdf
is decent (as are the other pages). Also good is
https://tutorial.math.lamar.edu/pdf/calculus_cheat_sheet_all.pdf
but at the end of the day is about listing/spotting possible approaches and working through a line or two (maybe in your head) to see what gives.

When it comes to integration, there really isn't one "rule" that magically solves all problems. That said...

- Substitution is often the most versatile - try this first before employing heavy machinery!
- Try IBP if you have a product of two functions, one of which you really want to differentiate instead of integrate, like ln(x), inverse trig, etc.
- Try Partial fraction decomposition if the denominator can be factored.
- Try Trig sub if the denominator has some kind of quadratic that can't be factored.

Note the emphasis on the word "try". Nothing is guaranteed to work.