When practicing it helps to try and create a separate space for practicing to help you to focus. This doesn’t have to be a purpose built studio or room but somewhere where you won’t get distracted and can really get into the mindset for practicing.
Ideally you also want to be away from the computer, I dunno about you but in this day and age having facebook, twitter, google+, eMail, youtube etc. within reach is just far too distracting
If you do need to use your computer then shut down any distracting apps/programs.
Wearing headphones can be another way to try and shut out any worldly distractions as well as shutting off that mobile. This is your quality practice time afterall.
Recently I’ve got back into a regular practice regime and now move away from my desktop computer, using my iPad as a practice tool. As well as displaying any TAB, notes etc. I can also control iTunes from the iPad too, if I need to pop on any backing tracks etc.
I’ve found that this has helped me to concentrate and focus more, digesting the practice material better.
We need a free physical space as well as a free mental space, this way we can get the best out of whatever practice time we can spare.