Messy layout? Invest in some storage for your makeup - it may seem like a useless purchase but you'll probably be more inclined to actually use your makeup when you can access it easily and see what you have. Muji acrylic clear storage is great but there are lots of cheaper options available. I made a post a while back all about finding more affordable acrylic makeup storage . If you have a pull out storage drawer (mine is the Micke desk from Ikea) then try some cutlery trays or drawer dividers to organise your makeup collection.
What do you actually use?
Having your favourite go to makeup items in a separate place means it's always easy to find them but why not switch things up every now and then. Perhaps you could swap out your blusher this week, and maybe your bronzer next week. Having a whole bunch of makeup is pointless if you don't use it, so try your best to rotate products and make sure you actually get use out of them!
Throw it out! it's a good idea to have a good look through your makeup and condense your collection into products you actually use/will use sometime soon. Makeup does have an expiration date, products like mascaras and eyeliners usually have a maximum of 6 months after opening so it's a good idea to throw and older products away. Every item has some kind of expiration date; you don't have to stick to it although the recommendations are there for a reason. Of course, you can usually tell when a product is past it's life but make a point of regularly going through your makeup and sifting through the items that need to make a one way trip to the bin.
Products you don't like? We all buy things hoping to find our new favourite product and it doesn't always work out, in fact I've recently posted about some products I regret buying. Go through your collection and see if there's anything you really don't like/don't use - maybe it was the wrong shade, made you breakout or just didn't suit you. You can always give this to a friend/sister/mum who you think will enjoy it or depending on the condition of the item you could always host a beauty blog sale.