Trust your instincts. You will learn their crys and what could be the matter, chances are you spend the most time with the little one and you know them the best. If you think something is wrong, call your Dr's office. The nurses are there to help you. They understand first time parents and can offer good advice, but above all trust your gut.
Make time for hugging and laughing. These two things can turn a terrible day around. Even if it means you have to make funny faces and tickle your toddler, both of your moods will be better afterwards.
Don't be afraid to ask for help. Parenting can be overwhelming. Make sure you have a support network to get you through. (This should include your spouse; but for him to be the best support for you, make sure you still have time for him:).
Pray. Ask for help outside of yourself. You will need it.
Take lots of pictures (and save them on more than just your hard drive, you don't want to loose everything if your computer crashes).
Enjoy every moment. Time passes too quickly!