The hardest thing is starting to exercise. We've all been there. We're all guilty of spending a ridiculous amount of time thinking about exercise but so little time actually doing it. I've found that the best jumpstart is to just do 10 pushups either starting on your knees or not. Do 10 pushups three times a week. As a matter of fact, if you have the time to read this, get off your butt right now and do 10 pushups. Seriously, actually do it. Now. If don't so that then just give up and don't come back.
If you've done your 10 pushups, "say thank you sir may I have another" out loud, bookmark this page and set a reminder to come back here three times a week to reread this... and redo your push-ups. Do that for a month and then read deeper into this site.
The return on investment for doing the above is huge.