Marketing is a big, big topic. There are a variety of good online references you can start with before spending money at the bookstore. Try searching for "marketing tips," etc. in a search engine. Also, this forum has thousands of posts with marketing ideas that have been tried over the years, including feedback on what has worked, what hasn't worked, etc.
I am new in the screen printing community and on track to be printing in about two months. I know marketing is 90% of the battle so does anyone have any rec's for good marketing/communication/branding books?