Following the crowd and Motivation and success
I think the best way to practice is with a formula. Use the formula for anything they challenge you to do!
grab the attention with an interesting first sentence in the first para.
Express your main idea in the last sentence of the first para.
Make each body para start with a TOPIC SENTENCE.
Make the conclusion use a few words or phrases that you used in the intro para.
Follow that formula, and you will always score well as long as you know the rules of grammar.
Read Strunk and White's The Elements of Style
Read everything you can find by Dianna Hacker