This may sound dated and obvious, but a simple way to kickstart productivity is to know what you HAVE to do every day. That's it. If you don't know what you HAVE to do each day, you will expend your effort towards a lot of stuff that you really don't have to do.
So, how do you know what you HAVE to do each day? Well, optimally you will be following a project plan with distinct deliverables that you have to execute… Or you are working in a rote job that requires you to make a certain type of widget every day. If you are not in those two situations then you need to decide what you HAVE to do. Use context priority and other GTD approaches… And try and be realistic. That way you can get that HAVE to do done and have time to spare.
And when it comes to boosting productivity… I agree with other hints in this thread, but the thing that I find works the best is to walk away from things for a while and to work away from distractions as much as you can – and that includes Quora, Twitter, Facebook, and… Most of the Internet.