The one thing that takes Android miles ahead of iOS is the ability to customize the UI to your liking. Be it wallpapers, icons, launchers, boot screens or what not, anything can be customized. In fact, Android gives you the ability to unlock the bootloader on your device to install any custom ROM. Savvy, isn't it!
All the tips mentioned in this post do not require rooting, so you can start right away.
The fastest way to overhaul the Stock UI is to install a custom launcher. There are countless launchers available in the store, some of them feature app drawers, while others don't. The one we appreciate the most is Evie Launcher. It's a pretty lightweight launcher giving you a Pixel-like UI without the Google Now cards. You get a search bar on top for quickly finding apps or finding anything online. There's an app drawer which can be either sorted vertically or horizontally. The developer has been regularly feeding updates so it's a pretty decent offering.
If you have a new launcher, it's time to get a new icon pack from the play store. Just like launchers, they are available in plenty. Type icon packs on the search in Google Play Store app, and you will be presented with options ranging from Pixel style icons to Lines based icons. Choose the one which suits best with your installed launcher.
This is one needs no mention, but we will let you know the best wallpaper apps to find one perfect for your persona. The top one on the list is Backgrounds HD (Wallpapers) by OGQ. It's the best-rated wallpaper app with a collection of countless wallpapers in various categories. If you want something unique, Walli - Wallpapers HD is another app, you can install.
If you aren't done with customizing and still want to do more, widgets will help you do so. With the help of widgets, you can decorate your home-screen with beautiful clocks, weather info, and much more. Lastly, you can try various lockscreen apps if you aren't fond of the stock one.