First you have to be committed to actually developing the idea.  Because distractions are everywhere, if you are really determined to avoid work you will find things to distract yourself with even in a completely empty room.

Then set aside some time to work on it, and/or a place to work in, and treat this time seriously.  Set an alarm and when it rings then you have to immediately get up and work on your idea for 45 minutes.  Starting is the worst part so you have to put all your effort into just getting up and starting.  Don't try to convince yourself of anything, think as little as possible and just start. For 15 minutes or so it will probably be awful and you'll want to quit but once your brain sees that you're stuck there for some time, it will settle down.  Don't let it check the net for just five minutes, or turn on anime, or just look at this book, or play with this toy.  Make it work.  After 45 minutes if things are going well then you will want to keep going, and if they're not then you can quit and do something else and go back the next day.  This way you'll at least be 45 minutes further along every day.  If there's a special occasion, don't worry about it, but get back to the routine the next day.  Eventually this will be a habit and you'll just do it.

There are programs you can download that can actually restrict you from going onto certain websites for a set amount of time like facebook, tumblr, youtube etc. 

I really suffer with getting distracted and procrastinating and I find it a real problem when it comes to trying to complete things. My best advice for you would be to not try and force ideas or motivation. If you're constantly trying to force an idea, it's never going to happen and it'll just frustrate you further.  Maybe try going for a walk to clear your mind and maybe look for some inspiration there. 

Another idea could be to look at the work of Keri Smith. She has multiple books that give you small creative tasks to help get the creative juices flowing or for you to try some new things. I'd suggest maybe looking at 'How to be an Explorer of  the World'. I find a lot of inspiration with her books and tasks so maybe it'll work for you. I hope this has helped at all and keep trying!