Exchange 2010 Server Maintenance

I was wondering if someone can point me in the right direction for server maintenance on my Exchange Server. I was thinking of rebuilding the catalog index, rebuilding the database, and performing an off-line defrag. I find pieces all over the internet on what to do. I was hoping someone can bring the concepts together for me and give me some guidance on a proper time line and when to do things. I have about 100 users at the organization, using OWA, Outlook 2010 and 2013, and mobile access on various devices. Any other recommendations? Thank you.