I copy paste what I wrote in your journal so it doesn't get lost among other journals:
I saw your wallpaper and despite it has simple shapes and composition compared to most of other entries, I personally liked the vibrant colours inside each geometric shape but if I may give you a bit of constructive criticism that I feel to point out is this: what makes the work a bit messy in terms of overall look is the composition. A well-composed work is clear, concise, and interesting. All the pieces will appear to work in perfect harmony. It will look like a cohesive painting, rather than an arrangement of parts like I've noticed in your work.
Composition theory can be distilled down to two basic questions:
1) What do you want to say?
2) How are you going to say it?
Start always with these two questions. What did you want to capture with your drawing? And how are you going to say it?
Remember the visual elements of an artwork are the building blocks of said artwork and they are: line, shape, colour, texture, depth, value and space. Because each chromatic part of the background give a messy-like vibe to the composition the viewer can't focus on the main subject of the wallpaper (Fancy Pants in this case, if I recall well his name, lol). The colours don't help the eye to focus on him.
A good solution for this might have been working on perspective and focal point. The lack of a focal point (maybe a primal focal point around where Fancy Pants is) makes your work not have any real direction or purpose. Where to put your focal point? Well, Rule of Thirds rules, sorry for the pun^^
What is Rule of Thirds?
What it entails is cutting your reference into thirds both ways using two horizontal lines across and two vertical lines down. You will end up with nine sections. Here a fine example of this rule:
https://drawpaintacademy.com/wp-content/uploads/2017/09/Renoir-Monet_painting.jpg
this is Pierre-Auguste Renoir, Monet painting in his garden at Argenteuil, 1873. There are two important ways you can use the rule of thirds to improve your artworks:
1) First, you are provided with four intersections where the lines meet. These are very important intersections as they are the generally preferred areas to place your focal point. This is because these areas are slightly off-center but also not on the edges of your painting. If you place your focal point in the center of your painting you run the risk of creating an unnatural composition. If you place your focal point on the edge of your painting, then you run the risk of directing the viewer out of your painting, rather than through it. Here the same painting with the intersection highlighted:
https://drawpaintacademy.com/wp-content/uploads/2017/09/Renoir-Monet_painting2.jpg
2) Second, you should try to ensure each section is unique to some extent. If you have two or more sections which appear very similar, then your composition may appear bland.
So if we want to apply this to your work we will have something similar to this:
https://imgbox.com/vZORI0de
I did a screenshot of your work from the collab and applied the Rule of Thirds. The blue intersections are the areas where you can put your focal point. In the Rule of Thirds all the sections are unique in some way. In your case the excessive use of bright colours and same basic geometric shape make the bg look a bit bland. So how to possibly fix this?
1) Framing (arranging shapes and other elements in a way that “frames” a particular area)
2) Leading lines (suggestive lines that direct attention around a painting)
3) Simplification (t involves taking all the “noise” and detail and simplifying it into something more coherent)
By simplifying the unimportant, you focus attention on the important. And I think in your case simplification is the way, how?
use a limited color palette (simplification of color)
compress the value range (simplification of value)
use larger brushes (simplification of tools)
use less refined strokes for unimportant areas (simplification of detail)
I think in your case a more limited colour palette and a right-positioned focal point towards Fancy Pants would have helped making the composition more balanced and dynamic.
Sorry for this long ass comment but I genuinely felt sorry seeing a young and enthusiastic person getting treated like that. I get that sometimes even a more blunt critique may help but people should understand that not everyone reacts the same if treated that way and I find the way he treated you discouraging.
Keep it up with practice and fun, one day you will be amazed by the progress you have made!