I recently designed the user interfaces (UIs) for a weird videoapp called Chatparty.
Here's how I design UIs:
What do I want the user to do?
For Chatparty, I wanted the user to enter a video chat room.
Get your user from point A to B. From the home screen to main product.
Now you know the goal. What are the essential steps to get there?
For Chatparty, it was:
You want to get your user from point A to B in a straight line.
For Chatparty, it was: Home screen > Sign up > Create a chat room or Join a chat room
You may be rolling your eyes like "Obviously". But just remember, hindsight has 20/20 vision.
Building a LEGO castle is tough without any LEGO pieces.
So you gotta go get some LEGO pieces.
Viewing the work of others gives you those "LEGO pieces" to build with.
I look for products that solve the same problem and then I, frankly, steal from them.
Don't worry, it's for the love of the art.
I imitate what works.
For Chatparty:
Now that you know the essential functions and you have a couple muses you want to paint.
Sketch it out.
Start with the feature, not the layout.
So for Chatparty, I started with the chat room feature. I sketched in a notebook, how I imagined that would look like given the goal I had in mind.
"Chat with the other users using the text chat"

I love love love Figma. It's like if Canva & Adobe Photoshop had baby.
I can be tough to get a hang of for a while but it's worth it.
Build out your sketches using Figma. It doesn't have to be perfect. It just has to be a rough estimate.
It's not your product. It's just a more detailed, digital sketch of what your product could look like.
This was what my Figma mockup looked like for Chatparty's chat room:

After that, you or the developer on your team, codes it out.
Here's how the chat room UI ended up looking like:

Shadow clones sold seperately.
🎯 Figure out the goal
🏃♂️ Figure out the main functions to get to that goal
🎨 Seek inspiration (and steal)
✏️ Sketch it out
🛠️ Build baby build
Nothing beats Pen(cil) and paper. I like the steps you have given and it might be helpful for a lot of us. Thank you, @antdke :)
Yeah, I love pen and paper too. Offers so much freedom. Even carry a paper notebook with me for sketching ideas. Keep my designs, ideas, todo lists and more on paper. Designed a habit tracker on paper and even launched some ui sketchpads for my customers last year.
Agreed! & no problem:)
Regarding "seek inspiration (and steal)", I often go through competitors and related websites/apps, take screenshots, then in Google drive I add big red boxes & notes of what I like/dislike. That helps me and I figure it's good documentation for if/when I hire a UI/UX professional.