We start with a couple of examples of tactics. One key tactic is to threaten two or more things at once, commonly known as a fork after the multiple prongs on a fork. This can often be too hard to effectively defend against.
How can White to play fork to get a favourable ending?
Here’s a real example of a terrible blunder allowing a fork and prompting resignation
If you’d like to see more puzzles then one source is the ECF website which has bronze and silver puzzle and skill sheets to download: