If she has got a promotion or the sort, try to keep the gift a little formal, but of course, thoughtful. If she's relocating to another city, and you're searching for a keepsake, you can perhaps combine something fun, but with a little sentimental value. Now that you know the basics, let's see what your options are.
A small tent, the moonlight, and a fireplace―sounds like the perfect thing, doesn't it? Let there be no one but the both of you. Tell her what you feel for her and how special she is to you. Let this be a gift of promises and future plans. Let there be beauty to this night.
Sometimes, she must have discussed what she's always wanted to do and hasn't been able to. It might be traveling to some place, buying something, some sort of adventure that always excited her, or maybe a movie she's been dying to watch.
If she's been telling you to do something and you've been denying it all this while, now is your time to surprise her. If she has been wanting to buy something and is not finding it anywhere, hunt it down for her. Do everything you can to the best of your capability and make this happen for her.
Remember, gifts are not always items you purchase at stores. In those cases, all you do is pay for them; nothing else involved. There is no special thought that goes behind the whole gesture. So this time, choose from one of these ideas and make it special.