"When..........
I think ..........
I feel ...........
In the future, I would like .........."
Also, remember that there may be instances where your partner may not agree to your specific request which is when you refrain from demanding your way (like a 2 year old!) and work toward UNDERSTANDING and then negotiate for a resolution that will be as much of a mutual "win" as possible. In the end, the connection with your partner is the higher order priority than getting what you want!
Principle: When expressing a complaint, state the complaint without too much emotion and without attacking the other person (as factually as possible) and ask specifically for what change you would like. If they are not willing to do that, negotiate something that might be satisfactory to both. Goal will be to end up with the relationship supported (come out on the other side holding hands).
Next: Sharing Hopes, dreams, insecurities, fears