1. Do the “Productivity” sessions in the Headspace app. I was really skeptical about guided meditation, but have found them very useful in maintaining focus. It teaches you to be aware when your mind wanders and helps you bring focus back to the task at hand. https://www.headspace.com/
2. Force yourself to break big tasks down into tiny chunks. When things seem overwhelming, it's easy to put them off.
3. Consider using an app that divides your working day into chunks that you can work on in 30-minute intervals. I use http://focuslist.co/ to set my agenda for the day early on, then work through the list.
4. Read “Deep Work” and “So Good They Can't Ignore You” by Cal Newport.
5. Reduce social media. I dropped Facebook and removed all twitter apps from my phone. This is a good guide: http://humanetech.com/take-control/
6. Exercise for 20 minutes every morning. I bought a speed rope from http://rpmtraining.com/ and now skip every morning while listening to podcasts / audiobooks.
7. Consider getting a full-time job, or a contract with one company for 20-30 hours a week. Having co-workers to compare yourself with and managers to be answerable to is a natural motivator.