Here is a list of some resources to help keep the BAD-FI away. There are videos, blog posts, and white papers. The wireless community is so generous with sharing its knowledge. These are just some of the great things out there. 

• 5GHz Frequency Allocation (North America)

• 7 "Tricks" of Wireless Professional [VIDEO]

• 7 Rules for Accurate Site Surveys by @KeithRParsons

• 802.11 Arbitration by Marcus Burton. This is how WiFi works. (Should be in EVERY WLAN engineers library.)

• 802.1ac In-Depth Overview [VIDEO] by Peter Thorneycroft

• 802.11ac WAVES 1 and 2: A Reality Check

• 802.11ax for Dummies by David Coleman

• CWNPTV on YouTube

• Get Certified at CWNP

• Mike Albano's WiFi Client Capabilities List - a list of devices and their capabilities to assist in your wireless designs.

• MU-MIMO Overview by Jerome Henry [VIDEO]

• Andrew VonNagy’s Revolution WiFi's Blog

• Revolution WiFi’s Capacity Planner

• Revolution WiFi's SSID Overhead calculator

• RF Connectors: A Visual Guide from L-com

• Roaming Behavior for Apple, Samsung, & Windows 10

• Understanding Primary and Secondary Coverage by Devin Akin

• Ultimate Guide To Modernizing Classroom Wi-Fi by Keith Parsons

• Understanding common outdoor antenna types/patterns [VIDEO] by Aruba’s Chuck Lukaszewski

• WLAN Troubleshooting Guide by Dave Coleman. It’s actually the troubleshooting chapter from his and Davis Wescott’s CWNA Study Guide.,

• Why One AP Per-Classroom Is Wrong by Keith Parsons

• WiFi for Beginners Podcast by @WiFiNigel

• Wireshark most common 802.11 display filters by @VergesFrancois

• Understanding Behavior of Mobile Clients by Jerome Henry [VIDEO]

• WLAN Pros Conference Session Videos - if there's only one conference you can go to this is the one.