You can help mom by attending childbirth classes with her, researching names, creating birth plans together, and being supportive during delivery. If you are unsure about how to support mom, I recommend reading "The Birth Partner" by Penny Simkin. Also, it is okay to ask for help. A doula can help you make mom feel comfortable before, during, and after the birth of your baby. She doesn't take your place, but helps you to help mom get thru this journey. It is much easier when the whole burden isn't on you. Doulas are team-players and offer many great tips and solutions to comfort mom.
I also offer a 2 hour "Dad Prep" class for any dad-to-be. Whether you are having a doula or not, I can teach you how to be a supurb birth partner. "Dad Prep" course does require mom to be there. You will learn: comfort techniques, massage, communication, and how to ultimately help bring in your bundle.
As a doula and childbirth educator, I am available for questions. Please visit my website for more information.