The Azure team recently announced some new features in the preview portal:

https://azure.microsoft.com/en-us/updates/get-early-access-to-new-portal-features-2/

Of particular interest is the new Subscription Usage + Quotas view that displays a graphical view of your subscription’s current limits:

You can filter the list by service, provider, and location, and restrict the view to only those items currently used or all items. The page has a handy link to initiate a quota increase request. Additionally, you can sort by the Usage column in descending order to get an idea of the quotas that are nearing their limit. This is extremely useful for planning future usage increases.

The preview portal is located here: preview.portal.azure.com

For more detailed information on quotas, please see the following documentation: Azure subscription and service limits, quotas, and constraints