After Effects is a very resource-demanding software. Here are a few ways you can improve the render speed.
1. Close other programs
After Effects is CPU-intensive software and you can close all other programs that are unused or work in the background to free up resources.
2. Change the resolution quality
You can change the resolution quality in the preview panel. It is common to work on a quarter resolution or even 18 of the quality for very heavy projects. 
It is enough to see your changes and it will be full quality on the render. You do not need to worry to change it back. This option affects only the After Effects preview.
3. Solo a layer
If you are trying to edit a specific layer, you can solo it so After Effects does not render all other layers, and effect. 
4. Region of interest
If you’re working with a specific area on the composition you can isolate this area so After Effects does not render anything else. 
5. Reduce project
You can remove unused items to make the project work faster. ==IMPORTANT!== We recommend saving a copy of a project before doing it. First, you must select all folders, compositions, and footages that you DO need in your project. Then press File – Dependencies – Reduce Project. It will remove all unused items in your projects automatically. 
In case if you'd like to remove the only unused items from AEJuice, press the remove unused button. n 
6. Add disk cache
Go to Edit – Preferences – Media & Disk Cache 
Enable disk cache n 
Pro tip: it's best to select an SSD hard drive rather than HDD for the cache. You can change the disk by clicking Choose folder. n
7. Import pre-renders instead of projects
Right-click on the animation in the Pack Manager and click Import as video. The plugin will import a video file instead of an editable project. It will speed up the editing and rendering. Please note this option is not available for all animations. It will be greyed out if it’s not available for this particular animation.
8. Keep working on projects on the SSD drive
While you’re working on the project it’s best to keep it on the SSD drive to speed things up. Once you’re done with the project you can move it to an HDD drive if you don’t have enough space.
tip
Keep the system SSD separate from your project’s SSD. It will increase the read/write speed.
9. Use AEJuice Freeze Frame
How to freeze a frame in After Effects
10. Profile slow layer
Starting from After Effects CC 2022 you have an option to profile layers and see which one layer or effect is the slowest.
Right-click on the timeline – Columns – Render Time 
Here is the slowest layer 
Now you can optimize it manually.
