Press F11 on your keyboard to make this fill your full screen. This gets rid of distractions. Also, put your phone onto flight mode. If there's an emergency over the next few minutes, the president will find a way to reach you.
Choose your typing speed. Slow Medium Fast
Choose a question you want to answer in this 150 word block:
Choose between 2 and 6 words or phrases you want to include in your text.
1.      2.      3.
4.      5.      6.

When the next page loads, start typing immediately, and don't stop typing.

Do not edit as you go, and don't stop to correct spelling/grammar.

Keep the green (word count) bar ahead of the blue (time) bar.

When the time is up, or you have reached 200 words, you can go back and edit down to 150 words.

Take a deep breath...