My style is done just using Gimp for the images, tweening functions on the gui objects for the movement, and the tween service for other types of movements such as rotating, I also use viewport frames from time to time as well.
An application center I made for an SCP group.
Style: Minimalist (I took a lot of inspiration from YouTube)
Program used: Roblox Studio
Pictures:
I use Roundifier by @MENETHIA but I think it is no longer supported.
I’ve been getting myself into UI designing myself and tried a couple applications and websites, found one I’m happy working with. I ended up making a little window that I will end up using someday.
(I had nothing good as a placeholder icon, so I used that one)
I plan on making more than just those 3 components, but I still need to work on my creativity before I can do that.
Contrast issue on that notification UI. It’s quite obvious.
Cheeky buttons 
Ignore that ugly logo placeholder, lol
Programs used:
Style:
Image:
@TheLoneNeighbour The GUI doesn’t look the best, in my opinion it’s too dark. and with the “locked” options the lock just seems out of place. However, as a start it looks good. 
@Shardwielder Woah, that looks pretty cool, only think I can really suggest is to make it more fluid, make animations when you click buttons rather than it instantly showing a box, it could bounce in, it could fade in or something - play around with effects.
@ItsMatko I know this is only a mockup but rather than having so many thick dark lines, you could remove the bottom one and just make the title area a light gray, here’s a quick example I’ve done.
I made some simple guis, toke like 2 hours in 2 days to make. 
Wow, your UI looks fantastic I can´t wait to see your game.
@So_er The only suggestion I can really make is the contrast, some people may struggle to read the text, if they have a visual impairment. Have you tried making the text white?
I know it looks small because the thing I took a pic with is bad.
But thanks for your feedback!
I don’t think he was talking about your UI. 
If you’d like me to make a more indepth look, just shoot me a Direct Message & I’ll quite happily review it further for you.
