Set your goal to just work out for at least 10 minutes - and do it even when you don't feel like it. It's only 10 minutes, right?!? It's not going to kill you!
For me - when exercising I get energized. If I trick myself (even consciously) into JUST getting started - that 10 minutes can easily stretch to an hour or more. On those days that I just can't get with it - at least I get 10 minutes in.