Tips to Reduce Email Size and Avoid Clipping for Newsletters

Any advice? I'm new to this and a few newsletters in, but I'm struggling with email size and clipping. I see newsletters like The Donut, The Neuron, Morning Brew and others pack their issues with images, gifs, links, blocks of text & emojis, but the email size is never that big (usually comes in around 120kb.) Mine always comes in bigger and gets clipped. The test email I send is fine, but the actual email I send out to my list suddenly jumps by about 30kb. Does anyone know how these newsletters manage it? I've followed the advice in the knowledge base, removed trackers from links, compressed every image as much as I can, reduced word count, but it's always a struggle. Are there common practices that I'm missing to keep email size down?