Simple loop puzzle book - solving strategies

For those who are new to simple loop or any loop-making puzzles, then they can be a bit daunting to the uninitiated.

The easiest rule to use is to look for instances where the loop can only enter and exit a given square in one way - ie the loop can only go into one neighbouring square and be entered from one square - since the loop must pass once into and once out of every square, these can be marked in straight away.

This means the four corner squares can always be marked in trivially, and likewise the same logic can often be applied iteratively to make good progress with the rest of the puzzle.

Another good rule to use is the idea of isolation - if putting the loop in a certain direction would mean it couldn't reconnect to the rest of the loop, then that is clearly not a valid option. Anything that would lead to the loop closing prematurely (and thus the puzzle would split into at least two loops) is also not allowed.

Sometimes you might need to look ahead a move or two, but all the puzzles in the book have a single solution and any lookaheads are kept within a sensible threshold.

What other rules have you come up with to help solve simple loop and other loop making puzzles? We'd love to hear your thoughts on this!