Hook Material
I'm not sure if this will help but just wanted to provide my two cents.
A hook should be something memorable, and catchy (obviously) since it's often times in the title of the song and sums up the idea of the song. Try using a phrase or expression as a part of, or as the full hook. Everyday common phrases are good, but run the risk of being a bit too cliche. On the other hand, hooks that are too esoteric or obscure run the risk of not being understood by the audience.
To get started, I would give these three bits of advice:
1) Try writing your hook FIRST. This will inform you for what the rest of your song is about. Since it sounds like you have a much easier time coming up with verse material, it may be helpful to write the hook before you establish your verses. This will also help to keep your verses focused and on point, so that the hook (the most important part of your song) is being supported by your verses rather than sounding like an afterthought.
2) Try looking through outside material (newspapers, magazines, online articles, blogs, etc...) for phrases or words that catch your attention. When you see a phrase try using it to write a hook - put a melody or a fragment of a melody to the phrase you found. If the phrase seems to suggest a certain rhythmic feel start by using that to place the phrase in a musical context.
3) Don't force it. Only use phrases that speak to you and your inspiration. The great thing about this exercise is that you can give the same article to ten different people and they will likely come up with ten different hooks... so trust your instincts and use what comes naturally!
I hope that this helps. Best of luck to you!
-Hans