From Office ProPlus to SharePoint to Skype – understand which apps you’re using and how much bandwidth they consume. This is the traffic you must optimize separately from other traffic.
Send all your Office 365 app traffic directly to the internet locally and don’t route it through a central gateway.
Microsoft recommends not sending O365 traffic through your security appliances. This can trigger costly throughput upgrades, creates latency, and hinders performance.
Make sure your remote users go directly to Microsoft. VPN hairpins add far too much latency, which kills the user experience.