Hang on! 1
Do you see this bit of brilliance here? Why has it never occurred to me to hang spray bottles from a tension rod under the sink?
Use the door! 2
If these over the door organizers work for closets, why wouldn't they work for under your sink.
Build it in! 3
If you are handy you could totally build in some storage under your sink that keeps everything organized. If you are not handy, you could get someone else to do it for you.
Pull it out! 5
Getting something from the back is always hard, unless you install one of these pull-out shelves under your sink.