I find it helpful to resolve an issue by starting to write an email or forum post (or a blog post) to ask for help or complain about it. Trying to write an explanation for what is happening so someone else might be able to help me focuses my thoughts. Very often I find it isn't necessary to finish writing.
The answer presents itself during the writing.
Next time you're puzzling over something, consider writing down what you think is wrong and the solution may arrive as you type.
Worth mentioning that a short break can also help a lot. Grab a beverage, talk to someone else, or stretch your legs; or all the above. The change gives you chance to work on the problem in the background of your attention.