With Stylish in your browser, go to my Custom Characters theme:
https://userstyles.org/styles/113824/myanimelist-add-custom-characters-on-the-sides
When you go to the page, you'll see a lot of choices of character and background (under
Choose left character, etc). You may want to initially install the theme to test it out and see it add characters to your view of MAL. But you probably want some ecchi characters instead, right?
To choose from a wide variety of ecchi characters, refresh the page and click the bubble next to
Provide your own under
Choose left character. Now open up my Ecchi character album on Imgur:
http://imgur.com/a/tdRKX#0
And find the character you want for the left side. When you found one you want to try, right click the image and choose
Open Image in New Tab.
It'll take you to a new page with the direct view of the character. You copy the address (this is the direct link URL to use this character).
And paste it into the box next to
Provide your own. This will be the character on the left side now after you hit the green Install or Update button on that page!
Do the same with the
Provide your own under
Choose right character. When done, click the green Update or Install button down the page. If you don't see the button, refresh the page or make sure you did step 1. When you visit MAL again, the pics should be in your view! You can refresh the page again where you installed the theme, and try new characters and combinations.
You can also use URL links to other images you have online instead of ones from the album, or click the browse button next to
Upload your own to use an image on your computer (make sure you click the bubble next to Upload your own as well if you're going to do this instead.
They need a beach!
Now you can add a background to suit your new look. Check out my add a background theme:
https://userstyles.org/styles/113507/myanimelist-customize-background-image-and-color
It works the same as the theme where you added characters. You can also try a variety of other backgrounds from my scenic background album here:
http://imgur.com/a/P9BFr
By now, you've got a pretty cool MAL theme probably with your choice of characters and banner (if you had problems see the FAQs or ask and maybe someone can help you). With my additional Stylish scripts, you can do a variety of other changes like removing certain links, removing the footer (blue bar at the bottom) and other parts:
http://myanimelist.net/forum/?topicid=453219
https://userstyles.org/
You can search the site for themes for MyAnimeList or other sites, like the dark and red theme from the examples on top. This theme is compatible with any of my themes that add backgrounds and change parts of the layout:
https://userstyles.org/styles/68300/myanimelist-net-dark-theme