I’m sure this is common knowledge, but it’s worth noting that whilst doing keyword research using Google’s external keyword tool you can use negative keywords like so:
This is useful if you want to refine your keyword list before exporting to CSV. Also, when you tick “only show ideas closely related to my search terms” it tends to return ideas that are almost exactly related to your search terms, which can be too limiting. This way you can use negatives to manually remove suggestions from the list generated by the keyword tool.