add slightly more detail in MQTT documentation, provide more concrete example

README.md

@@ -132,14 +132,29 @@ true%
 To configure your ESP to integrate with MQTT, fill out the following settings:
 
 1. `mqtt_server`- IP or hostname should work. Specify a port with standard syntax (e.g., "mymqttbroker.com:1884").
-1. `mqtt_topic_pattern` - you can control arbitrary configurations of device ID, device type, and group ID with this. More detail is provided below
+1. `mqtt_topic_pattern` - you can control arbitrary configurations of device ID, device type, and group ID with this. A good default choice is something like `milight/:device_id/:device_type/:group_id`. More detail is provided below.
 1. (optionally) `mqtt_username`
 1. (optionally) `mqtt_password`
 
+#### More detail on `mqtt_topic_pattern`
+
 `mqtt_topic_pattern` leverages single-level wildcards (documented [here](https://mosquitto.org/man/mqtt-7.html)). For example, specifying `milight/:device_id/:device_type/:group_id` will cause the ESP to subscribe to the topic `milight/+/+/+`. It will then interpret the second, third, and fourth tokens in topics it receives messages on as `:device_id`, `:device_type`, and `:group_id`, respectively.
 
 Messages should be JSON objects using exactly the same schema that the REST gateway uses for the `/gateways/:device_id/:device_type/:group_id` endpoint. Documented above in the _Bulb commands_ section.
 
+##### Example:
+
+If `mqtt_topic_pattern` is set to `milight/:device_id/:device_type/:group_id`, you could send the following message to it (the below example uses a ruby MQTT client):
+
+```ruby
+irb(main):001:0> require 'mqtt'
+irb(main):002:0> client = MQTT::Client.new('10.133.8.11',1883)
+irb(main):003:0> client.connect
+irb(main):004:0> client.publish('milight/0x118D/rgb_cct/1', '{"status":"ON","color":{"r":255,"g":200,"b":255},"brightness":100}')
+```
+
+This will instruct the ESP to send messages to RGB+CCT bulbs with device ID `0x118D` in group 1 to turn on, set color to RGB(255,200,255), and brightness to 100.
+
 ## UDP Gateways
 
 You can add an arbitrary number of UDP gateways through the REST API or through the web UI. Each gateway server listens on a port and responds to the standard set of commands supported by the Milight protocol. This should allow you to use one of these with standard Milight integrations (SmartThings, Home Assistant, OpenHAB, etc.).