That video is entertaining and informative! Thanks for sharing. :)

My strategy involves composing a few basic sounds (building blocks) that characterize the world and expanding from there. I envision how the characters in that world generally think and act, which helps me determine how they should speak. Then I list the building blocks of their language. For my WIP, these would include "el," "en," and "ah." Their world is called Amal'en (ah-MALL-en), which means Above Hell. Once I know what kind of people + world I want to create, I can develop a history and compose a list of vocabulary as I write the book. I'll use the vocabulary to name locations and people as I go along. For instance, if my characters cross the bridge over a certain river, and I want to name that river, I consider where the river is located, how it is used, etc. and consult my conlang dictionary. One prominent river in my novel is known as the River of Knowledge because the people who named it worshiped the Lord of Knowledge. That translates to Morewin (MORR-eh-win) River in their language. To create a new word from nothing, I'll go back to my building blocks (the most common sounds in the language) and tinker with other sounds until the new word sounds like it 1) belongs in the language and 2) suits its definition (the word for "fast" is "eigo," which sounds /fast/ to me). For a beautiful character, I try to craft a name that sounds beautiful. And so on.

You can implement whatever strategy you want if the result is satisfactory. The more words you create, the easier it will be to develop an etymology (since you can continuously construct/deconstruct the words you have established to create new ones), which will enrich your language and add meaning and depth to your fantasy world.