So what I've come up with is my own method that has helped me build my attention span. I believe it will work for others too if their serious about it. Here it goes.
Write a word down on a piece of paper that means a lot to you. Next look at the word without having your eyes move away from the word. Time how long you can do this and write it down. The first time will be your measuring stick. Keep doing it and trying to increase the time you can stare at the word without looking away. Don't move your head or eyes in any way. Your eyes must stay focused on the word. There can be no eye shifting of any sort. No looking up, down, left or right. Also quiet your mind as this tends to help.
This is very simple and it's an actual technique unlike what I've found when looking on the internet. It seems simple, but you'd be surprised at how hard it is to do. If done consistently it will help you build your attention span and you'll be able to focus better. Try it. feel free to write what your first few attempts were in terms of the time you lasted.