For the singles and the unhappily married's, focus on YOU means find something to do FOR yourself or give to yourself. And I deeply recommend that that thing you give to yourself be an emotional, rather than a physical gift.
Time doing something YOU like is tops of the scale here.
Netflix movie bender of your favorite movies + your favorite meal all ending in a bath (using that bath oil that you never use because it was an expensive gift). Perfect!
The secret to giving yourself an emotional gift for Valentine's Day is in feeling that your actions are NOT a substitute for someone else's missing love. You are not the, "darn, this is what I'll get instead..."
You are in fact, practicing identifying what you most love and receiving what you most love.
These are skills that need to be well honed for you to get into a happily mated relationship anyway. :-)
If you're in a dating relationship, most people will caution you not to do too much for your mate. If you have to toe the "not too much so I don't scare you" line super carefully, you may want to consider truthfully how that relationship is going. (Next month is all about truth!)
Just be sure you are not giving to exert control and "demand" more from them than they have ALREADY been giving to you emotionally.