I recently got this book: http://www.amazon.com/Paint-Vibrant-Watercolors-Twelve-Lessons/dp/0062336320 and I found it pretty useful for the drawing tips/what colors to use. There's review of the book with some screenshots of the pages here so you can decide if it'll help you too: http://www.parkablogs.com/content/book-review-you-can-paint-vibrant-watercolors-twelve-easy-lessons