While the question "How to get mentally tough" can be a bit confusing, there are a couple of principles which can demystify this for you...
Be sure to check all 3- they complete each other to one big picture:
1.Emotional health precedes mental toughness-
This is the foundation of everything if you ask me. And I don't mean just depression or mood swings.
If you constantly feel bad about yourself, you'll have a "bad" mind as well.
You'll hate challenges and uncomfortable situations, and it'll be harder to develop a strong self-image because you're mostly passive.
Get the fundamentals right first:
-Do you sleep well?
-Eat well (REALL food)?
-Do you engage in physical activity?
Then, think about these:
-Do I feel good most of the time? How's my mood?
-Do I have unresolved emotions?
-Am I running away from certain issues/ ignoring challenges in my life?
Your goal is to make sure you build a strong foundation of emotional wellness.
Feeling good about yourself means you have positive self-image and generally loving your life.
2. Realizing failure is part of the process- Hear me out on this one.
I'm not telling you to go and fail until you get it right. That would be stupid.
But... odds are you will experience some type of "failure" sooner or later.
Almost everybody does.
It's a lot like playing new video game. At first you're likely going to suck at it and maybe even want to quit.
But if you stick around and keep trying- you'll eventually get good at it...
When something isn't going according to plan, our mind perceives these unpredictable events as failures.
Sometimes it doesn't even qualify as a failure, but it just feels this way for YOU...
Realizing these will help you put things in perspective and stay calmer.
"Failures" and mistake are part of the game.
They are OK.
Learn from them and keep going.
3. Focus on What IS instead of "What if"-
This one really changed everything for me.
When facing a big/new challenge,focus only on solving the 1 problem you're facing at the moment.
Forget "What if the sky falls down" kinda things.
For example if you're trying to build a new business, focus first on selling and getting clients.
Don't worry too much about providing the service at this point or massing up somehow in the future.
Now I'm not saying go sell websites development services if you've never wrote code in your life before.
That would be a hasty thing to do.
You need to know what you're doing and actually gain some skills.
But don't freeze there and do nothing just because you don't have a complete plan of action or you don't have 4 years experience in your field.
What if this, what if that... it never ends.
Can you see what's your CURRENT problem is? Good.
Focus on that.
What's the 1 thing that made you mentally tougher?