You can choose different wording if you like, but I always write the date and time, and then "Today, I..." And then write down the most important things you accomplished that day.
You can write down as many or as few items as you like, but make sure to include the things that are most important to you. And be careful to only include the positive. Only include what you did get done.

Write: "Today, I..."

Why? Because research suggests that the last thing you pay attention to before sleep will stay in your mind. This is the reason you should try to avoid reading the news at bedtime.
Giving yourself a jolt of positivity is useful any time of day, but it's a particularly powerful thing to do right before you go to sleep because that too will stick with you. It's sure to better your mood and increase your motivation, and that effect might even last through your mood the following day.

Make this the last thing you do before bed

Again, you can choose different wording if you like. But the important thing is that you choose one priority for the upcoming day. Even though there may be several important things you have to do tomorrow, you must pick the single thing that matters to you most. 
It can be challenging to do but it's an important exercise because it forces you to think through what really matters most. What's the one thing that, if you get it right, you will feel that you've won the day?

Write: "Priority for tomorrow:"

Similar ideas to Write: "Priority for tomorrow:"

Write: "Today, I..."

Use a priority matrix

Have one daily priority