Basically, it is a matter of practice and learning from mistakes. Reading also helps a lot. You could use a tool like Grammarly, but you need to be careful not to lose the learning from making mistakes. I hope this helps!

You have to think about in which timeline you wish yo speak. Is your story in the present tense (I eat), past( I ate) of future(I will eat)? Is the action is still continuing (I am eating) or completed(I ate) Making a drawing of a timeline with the English tenses and example sentences it's a great visual aid to understand how the tenses work. To learn about grammar I like to use Lingolia. In this site they offer a brief explanation of the tenses and how to use them with exercises for you to practice.

I agree with the two other answers: practice, re-read, and edit. You are doing great! Also, the difference with these two sentences: 1. I am going to take my driving test next week. You are stating a fact about something that will happen in the future (next week). You are confirming. You are making a statement. 2. I would like to take my driving test. You are making a statement about your INTENTION. This is something that you want to do, if it's possible. And yes, saying "I would like" rather than "I want" can be considered more polite. But depending on the context and tone of your voice, "I want" will not be considered rude or impolite.

Even when I am writing an essay, I often mess up my tenses. I think you just have to reread and be patient while finding mistakes. Also, you learn from mistakes, so correcting your own essay will help you improve more! "Would like to" is a more polite sounding ways to say you want to do something. "I would like to go to the park" = "I want to go to the park" // "Would you like to play?" = "Do you want to play?" or "Want to play?" "Be going to" is not similar to "would like to." I don't think "be going to" is used at all unless you say something like "I will be going to the store soon" which is a future tense sentence.