It's recommended to constantly connect segments or mark wherever segments wouldn't exist.
First step: things to look for to start solving the puzzle
Adjacent cells
Corners
Diagonals
Continuation: with known line segments/ x's, how to maximize what you can get through deduction
* This would not be true if and only if the loop has two squares.
** This would not be true if and only if the loop has four squares.
Finalization: remember, there's only one loop in the puzzle. As you connect lines, make sure you don't close a loop until the very end.
Advanced Details:
« Back to Slitherlink