The best way is to stop relying on motivation.
Here's what I do...
Write down what I need to get done and what I know I can get done in
15 minutes.
Close all applications, games, browser tabs, etc, except the tab(s) you need open to complete your task (if applicable).
Then, I'd visit a site like
this one, and set the countdown timer to
10 minutes.
I like to use the
Chime, as the Timer End Alarm.
So here's where the magic happens...
Work your butt off, towards completing that task.
No distractions. No TV, no games, no web surfing, no chatrooms, etc.
This is the time where you grind.
Chances are, you'll finish your task.
If not, then THIS is the point where your motivation should kick in, and you'll be determined to finish what you started.
It's hard to beat laser-focused, tunnel-visioned action.
Good "luck".