Ask HN: How to stay focused

I read everywhere that "focus is key" and people who do one thing at a time have higher chances of getting successful. It is very hard for me to stay focused on any one thing, I give excuse to people that "I get bored easily", but I think that is not true, because I want to focus, I just can seem to do it. I will start a idea build it to some degree, then jump on another one. As a result not getting any thing done.

I have tried all the most of the "tricks" Don’t break the chain, GTD, checking email only once etc by I get distracted easily.

How can I discipline myself to start something and take it to end, without getting distracted mid way. Or how can I stay focused?