First thing first, you need to have the willingness for writing which brings you motivation.
However, you still might have a problem to figure out what you want to write at the beginning which is the hardest part, also, the writing could be not easy.
Here, FOUR TIPS based on my experience would be helpful.
write it short
It is not necessary to write your journal on the whole page. It is easier and better to start with one or two sentences.--really brief summary.
set an alarm
An alarm is a useful way to mention you at the same time, and then you would gain a new habit.
record what you did in a day
Anything that impressive, interesting or important is what you need to write down. Can not recall any of them? Ask you questions like what did you do? What do you want to do? How is your feeling?
Don't worry about your diary would be boring or not.
review your diary weekly
How to improve your diary? Read it and try to find out the different way to observe your life, you might be inspired.
Anything else you can try besides your daily?
Food, travel, hobby, study/work, relationship, family...
Remember, your diary is a private place that you can talk with yourself. Or you could treat it as a BFF. Don't hide. Don't lie. Talk more, you know each other better.
Briefly, try to begin with writing ANYTHING! To start is MOST IMPORTANT!
