Being mindful sitting/working on a computer

I find being mindful while sitting on a computer very hard. Most movements with mouse/keyboard are happening so fast and intuitive that it's very hard to be conscious of what the actual intention (by clicking on/typing this or that) is; often this also leads me into restlessness or loosing track of time; I'm sure this is a common phenomenon. Are there certain tricks/tips by which one can be more aware while sitting/working on a computer?