Try keeping verb tenses constant. Don't switch between past, present, future, and so forth. Interesting story. The detail you went into was great
I agree. Here is an example:
Although the trainings we had were tedious and tough, I enjoy competing with others.
This is not wrong, but if you want a nice writing "style" you can do this:
Although the trainings we had were tedious and tough, I enjoyed competing with others.
Using the same verb tense does something soothing for the mind.
:-)
You don't really make any mistakes. This essay is solid, and it shows that you write well and think well.
Here is a lesson about how to write a compound sentence. Always use a conjunction and a comma:
We train at least twice a week, and each session is usually three hours straight under the hot, blazing sun.--- You had already used a conjunction, but I had to add the comma.