By no means am I an expert...I haven't celebrated a Valentine's Day coupled in over 10 years. BUT...I do have a little insight from years of observation & I believe it to be simple.
THE BEST GIFTS (unless you're into those high maintenance types)-
This applies to any type of gift. Something that shows that you pay attention to the likes/dislikes of your significant other and it doesn't need to be expensive! If they have a strong love of pizza! Order a pizza! Girl scout cookies...tis the season! If you've been together a long time and you want to drop some dollars have at it! BUT above all else remember the most important thing is your time and acknowledgment of the day! I've seen so many just say "all I needed was a card!". If you want to secure that...GET A CARD! Most Valentine's Day gifts are bought at last minute, but there are plenty of places to buy a dang card!
THE WORST GIFTS!
A - Anything with strings attached. Click here for my personal worst gift ever rant from 2015
B - NOTHING! Remember...at the very least...GET A CARD!