Most of these tips I found on internet (references) and a few of them I discovered doind some tests.

Incremental build

In a continuous integration build, I think it’s ok to execute incremental builds.
Probably, from all the tips, this will be the one that will cause the biggest impact on your build execution time.
On VSTS, you can enable incremental build by unchecking the clean configuration like the image below:
VSTS clean configuration

If you got interested to know more about incremental build, take a look at these links:

Disable windows defender real-time protection

When your build is running, open the task manager. You will see a process called Antimalware Service Executable using almost 100% of the computer process.

Disable windows defender for the project folders

Still on windows defender, add an verification exclusion to the project folders.

Disable windows defender for some .exes

If you are on you developement machine, add an verification exclusion to devenv.exe process. In build machine, add and exclusion to MSBuild.exe process.

Add all cpus for the compilation

Parameter /n on msbuild