It usually comes as a surprise that English, like other Germanic languages, doesn’t have a true future tense. We’re perfectly fine getting by with a combination of adverbs and modal verbs.
Keep it simple. One of the most common ways to mark the future is to use present continuous with a temporal adverb.
I’m meeting a friend for coffee tomorrow.
She’s driving into town tonight.
After coffee, we’re heading over to the mall to do some shopping.
These are completely natural sentences. Note the lack of will.
The biggest gotchas with present continuous are that you can’t use it with stative verbs and the future context has to be clear.
The most common way to mark the future in English is with [am / is / are] going to [do]. If you’re in doubt, use this structure.
You’re not going to be able to sleep tonight if you drink so much coffee.
I’m going to lose some weight after my vacation.
We’re going to stop using will in every sentence.
Regularly scheduled events tend to take present simple even when the meaning is in the future.
I missed the first train, but the next one leaves in an hour.
I get off work at seven.
We better hurry since the store closes soon.
There’s some nuance in the last example. If the store closes soon, there’s a sense that this is according to plan. You can add a dash of urgency or express that this is unusual by switching to is going to close soon. This level of detail is something better picked up from experience rather than memorizing rules.
Will would not sound natural in any of the nine examples I’ve provided thus far.
If and When
If and when indicate the future and aren’t used with will for future conditionals.
If it snows tomorrow, I’m working from home.
Call me when you get home.
Your English is going to sound a lot better when you stop using ‘will’ all the time.
This is a huge gotcha for Slavic and Romance speakers.
Should, Might and May
Modal verbs of probability are the hardest part of the future for non-Germanic speakers to master.
It should be nice tomorrow.
I might just stay home.
You may not like it, but we have to get groceries tomorrow.
Think of will as a noun to get a sense of its power: free will, the will to live, willing. The modal verb has lost some of this raw strength in modern English, but it helps to remember that in Old English will was used only to express a strong want or volition.
Think of strong promises:
I’ll be there for you no matter what.
I won’t back down.
The emotional feeling here is much stronger than a mere plan. For plans use going to:
I’m going to give up smoking.
He’s going to learn Python by end of the year.
Will is also used for instant decisions that had no previous planning and is a change from what you’re currently doing
Hey man, you want some weed?
Sure, I’ll take a hit.
We’re heading out for bike ride, wanna tag along?
Yeah, I’ll come along.
If you never use will again, your English would sound more natural than using it every single time you talk about a future event. That’s extreme, but if you start using present continuous and going to more often, that’s already a huge start.