L.W.
I recommend you go online and google Parenting With Dignity by Mac Bledsoe. Look for the book specifically for preschoolers.
I also recommend an excellent, easy to read book by Elizabeth Pantley called Kid Cooperation you can find on Amazon.com
I am a counselor for children and parents and I do a lot of parenting training groups and seminars and these two books (among others) are ripe with information I pass along to parents with great success. Feel free to contact me personally if you want referalls on other experts in your area of town who might help you if you need further assistance. Good luck! - L. W