Hey cakers, I'm wondering if anyone can advise me on how to get sides of cake level. After I stack my layers, I use a sharp knife to cut off the darker crust, but I can never get them perfectly level. It looks fine to the eye, but after it's iced, it's a little off. If I put ribbon around it'll have small gaps and just looks tacky. I have a leveler, but I just can't seem to get it perfect. 

I'm assuming you mean your cake is rising in the middle but not the sides.  Have you tried using Wilton baking strips to wrap aroung your pans before you put them in the oven to bake. These are a tremendous help in your cake rising level.  I have never had to trim dark pieces off the cake so maybe your oven is to hot.  Have you checked that the temperature of your oven is correct.  Hope this helps.  Doz

Here is a nice article about the topic. I started using homemade cake strips (made out of strips of an old towel) about five years ago... and has been a game changer... now the kiddos complain because the used to snack on the dome part... that now happens no more!

How to Get Perfect Flat Cake Layers - Preppy Kitchen

Like doz I have never felt the need to trim off the sides of my cakes.   Why do you think it’s necessary?