First determine how many lights you need. This is a personal preference depending on how bright you want your tree to be, but for this 15ft thin trunk tree we used about 300 lights.
Roll up each string of lights
To make the lights easier to handle, roll up each garland. Start with the end in your hand and create small, compact balls.
Attach your extension cord to the tree
Secure your extension cord to the bottom of the tree by wrapping it around the base or using a zip tie. Face the connector down do that rain or snow doesn't get in.
Wrap the lights from the bottom to the top
Wrap the lights from the base of the tree up. They should be evenly spaced, about four fingers apart. If you prefer more lights, move them closer.
Decorate all the main exterior branches
Instead of trying to decorate each branch, focus on the main outer branches. When you decorate a branch, double the space between each light, then fill in the holes by going down so that the distances are regular. (NP) Avoid crossing the threads. Look for junctions between the branches that allow you to make the lights go in the same direction.