The first thing to recommend is, use Viet Hoangs installation guides and his scrips, there are things like trusted itentity server certs which and needed for the commerce install that Sitecores default installation for 9.1.1 does not have:

• Sitecore XP 9.1 Update 1 – Step by step Install Guide on your machine - first install SC 9.1 Update 1
• Sitecore Commerce 9.1 Initial Release – Step by step Install Guide on your machine

Sitecore 9.1 update 1 issues

This post is dedicated to a wishlist of what we would like to see from features to documentation and everything in between.
Please feel free to comment below or email me on rdias@1digit.co.uk if you want me to add something to this list, correct me or let me know if a wish has been granted.