Easiest way to train yourself into it is have to do it 6 days a week for work
I seriously used to DESPISE getting up early and thought 8am was a bit of a stretch for me during my student days, but I work four days a volunteer 2 a week and have to be up at 6 for both. I hate it, but I've grown to just tolerate it because I have no choice. I can't go without sleep though, I used to be able to but at 23 I'm now too old... I go to bed about 9.30-10.30 and even 7 hours is too little.
Take today for example, I had a good 7.5 hours sleep but the meds I'm on make me sooo sleepy, I took them before I set off, was dangerously tired on the road and by the time I got to work (voluntary today) I was so exhausted and waiting for a client to show up so I could assess him I put my head on the desk and fell asleep for 2 hours... same thing happened the other week, I just sat in a chair and bam, I was out like a light, I swear it's close to narcolepsy now. Anti - depressants: don't mix them with epilepsy meds and co-codamol, just don't. Unless you have to, like me. urgh.