Sometimes it is easier to start working on something you already started at another time.
This also means that it is helpful to leave off working on projects abruptly rather than trying to necessarily finish them in one sitting or get to a stopping point.
Sometimes I find it helpful to set a count down timer and just work for a set amount of time and then just stop when the timer rings. Some people work for 25 minutes and take a break for 5 minutes. Other people find the optimal time for working is 52 minutes and the optimal break time is 17 minutes. Some people prefer to work in 90 minute intervals. When I do the 90 minute work time, I don’t set a clock for the break time.
This brings up the idea that people work better when they take their breaks.
Just setting apart time for working by being on the clock is helpful.
This idea of running down a clock for short periods of work and break time may work better when working alone.