Prayer is the second pillar of Islam, and applies to us as well. The Muslim prayer combines defined movements with defined text. Of course you are free to use the Muslim prayer as your prayer, but what I do is to use text from Old Testament that fits with the movements of the Muslim prayer. I spent quite some effort refining this, and this is what I came up with both in English and Hebrew:
I use the Hebrew prayer. You can use the standard Muslim prayer or my prayer or you can make your own. But whatever you do, it should fit with the movements of the Muslim prayer. Otherwise you won't be able to use it when you pray with Muslims.
How important are the gestures and different sitting positions to the prayer? Back when I was a kid, I prayed sitting down and occasionally closing my eyes, and I think that helps with focusing on the message of the prayer and nothing else.