Here is a novel idea. Flirt with your significant other. Think back to when your relationship was just beginning. Didn't you flirt with your partner as much as you could. Remember those looks you gave them. The teasing and the sexy hot kisses that are always present at the beginning of your relationship. Why don't we still do that today? Does our partner not mean as much to us anymore? Can I still flirt? These are all valid questions.
However showing your partner that they still catch your eye is an important part of your relationship. Flirting is an art form in itself and some people are better at it then others. Even pour flirting skills should not stop you from avoiding this important function. If you have to be silly with it and go over the top. Your partner might think you are nuts at first, but believe me it will make them feel important to you.
If you really need help go to the Amazon Side bar and pick up a copy of Flirting for Dummies. Even if you don't need help flirting this book might still give you a some form of flirting that you have missed.