Some ideas
- If possible, consider placing some of the project in a different Visual Studio solution and reference them in the current Visual Studio solution. The projects in the other solution would be ones that don't change or seldom change
- Try each of the following one at a time
- Exclude projects from a build (other possible options on this page).
- Under Tools -> Options -> Projects and Solutions -> Build and Run. up the number of maximum of parellel project builds
- Under Tools -> Options -> Projects and Solutions -> General, un-check "Always show Error List if build finishes with errors"
- Also if possible, start Visual Studio in safe mode to ensure no extensions are interfering with the build
- Try changing setting in the two combo boxes shown below