I'm plagued with daydreams of fame, fortune, etc. How do I overcome these delusions and temptations?

Sylvan has a point. The lives of famous people are not all that great. There can be a loss of privacy and freedom. Elvis Presley said, "I can't walk into a McDonalds." Think about how to get satisfaction out of life. If you can find satisfaction in your work, great. If not, keep looking. One thing that can help is to "stop and smell the roses," as they say. Appreciate all the nice things of daily life. The therapeutic use of a traditional Asian method called mindfulness helps with this. The philosopher Pascal said, "All the troubles in the world stem from the difficulty we have in sitting quietly alone in a room." People all over the world are learning the benefits of meditation.

https://www.youtube.com/watch?v=wqEM_jlDRZI 

Remember that there are no trivial jobs. We're all important. All that matters is taking care of our responsibilities, be they big or small.

There is nothing wrong with dreaming of these things.

Look into the lives of people that have those luxuries, and perhaps you'll realize that they are not much happier or fulfilled in life as you are. Wealth and possession do not equal personal fulfillment. 

The thing about wants and desires is they are true as chose them to be. What you want and what is, doesn't always match up, and in this there is the room for dreams. Dream on!