1) Deploy all Reports using Dynamics AX Power shell.
2) Delete label files from AOT - Dynamics AX 2012.
Solution provided in below two blogs are useful.
3) Scale out dynamics 365 operation On Premise installation.
4) SQL/Dynamics AX Administration.
a. Read this post to get currently running queries, this will help to identify if any blocking.
b. Read this post to get script for re-indexing and statics update for Dynamics AX database.
5) Management Reporter
a. This link is useful to Rebuild Management Reporter Database.
b. This link is useful to find MRDM synchronization issues due to bad records.