Set a schedule.
Make it whatever works, mornings, evenings, nights, whatever...AND stick-to-it.
If necessary, shower and redress in attire for a formal office job.
Do NOT break the routine ----- if you have nothing to write ---- just write ANYTHING ---- and keep returning to the target..... do NOT access the web ---- (unplug-cripple-net-software.)
For myself, on the first "big-one" when approval was given and contracts signed - I continued the ten chapters, of my responsibility...in a church office, between the hours of 10:00 p.m. and 2:00 a.m. - five days a week. No interruptions, no diversions, because I was renting "computer time" by the hour....there was a personal investment that required optimal use of the time.
Sincerely,
Gargoyle