Reserve early. Wherever you want to go remember thousands of people probably got the same idea. Call and ask if you will get a table in advance.

Have a plan. You should have a plan, why go to a restaurant when you can go to the place you kissed for the first and have a picnic, women love it when men remember. Also have a backup plan just in case.

Be prepared. You might go to your place and boxes of half-eaten pizza and unwashed clothes are a turnoff.

Don't spend more than you can afford. You don't have to buy her a diamond ring, small things like breakfast in bed show you care and don't cost a fortune.

Don't say this day is stupid. Even if you think you should be romantic the whole year not just one day, let her feel special, no one likes a nag. And if you make fun of guys buying expensive stuff she might think you're cheap, you cheapskate.

Spend the day with her. You gave her a necklace and left to spend some time with buddies? She will feel abandoned and remember that more than she will remember the gift.

Be a realist. You planned a hike cause she loves hikes? Check how she feels first, she might be sick and you making her do stuff won't be a great idea. A bubble bath? That's better if she's tired.

Buy her something unusual. It doesn't have to be expensive. If you give the same looking earrings every year she will not be impressed, but a framed picture of her favorite moment will be more than welcomed.

Take a shower and wear new and elegant clothes. Sweatshirt makes you feel comfortable but will make it look like it is just another day for you.

Buying sexy lingerie can be tricky. Firstly you will probably get the size wrong and she will get the impression you think she's fat. There are also many other things that can go wrong- she can think you consider her a slut, or that you are not satisfied with sex, or she might even be allergic to feathers and assume you don't know her at all. Summing up you have to know your girlfriend and adapt; and most of all have a nice day.