If you have ever been in a business class and learned about brainstorming strategies, this technique will look super familiar. I am just editing the process a little to make it more about songwriting. The idea is to take a word and then write associated words around it. Then that starts a mapping process where those associated words will have more associated words and so on. I will do one so that it makes sense. The easiest way to do it is in visual form, so your replies will likely be in picture form. We will spend a few days drawing out to various degrees. At the end, you will have a lot of words that all relate back, to some degree of separation, to the original words.
Here is how we will work this exercise. Pick up a book, any book. Skim through a random page and pick a word that jumps out at you. Then flip to a different page and do the same. Those two words will be our center circles. From there, you will draw a least 5 lines from each of those circles leading to empty circles and fill those words in with related words. Feel free to go out another degree of separation if something comes to mind. In the future exercises, we will use this same diagram and expand it further.
One note, it is ok to have adjectives and adverbs, but remember that nouns and verbs tend to be more powerful. Good luck and have fun!