Plan a car camping trip for at least your first excursion. You may be surprised at how much extra stuff you need to bring for baby, and while it's easy enough to toss in the car (or tent), it could be hard to carry on your back all day, especially if you'll be carrying baby too.
Make sure you have comfortable sleeping arrangements. Even if you're used to roughing it on the ground, this may be tougher if you usually sleep with baby, especially if you often find yourself wedged into funny positions in the best of circumstances at home. Consider an air mattress, extra layers of padding, or some sort of portable crib if you don't usually sleep with baby.
Plan for plenty of diapers. If you're used to washing diapers frequently or using a diaper service, this can be challenging. It might seem counterintuitive, but disposable diapers may be worth considering for camping trips, even if you don't use them at home. Sure, you might have to pack them up and carry them out, but they tend to pack smaller and lighter than cloth diapers. Plus, it's pretty easy to bring as many as you need.
Consider baby's food needs. Breastfeeding is almost as convenient in nature as at home. If you bottle feed, powdered formula is probably your best bet since it packs small and is lightweight, as long as you have a reliable source of clean water. If your baby eats solid food, don't forget plenty of easy snacks.
Decide how you will transport baby. Even if baby is crawling or walking, there are lots of things in nature that you probably don't want him or her getting into without immediate supervision, from poison ivy to dangerously inedible items. It can be a nice break to get baby up off the ground and transport him or her in a sling or wrap (or even stroller if there are level trails where you will be). Plus, if you plan to hike, chances are you will want to be able to move at a more adult pace.
Bring a few favorite toys. You don't want to over pack, but a few familiar items can go a long way towards entertaining and calming baby.
Apply sunblock liberally! Babies' skin is especially sensitive to damaging solar rays, so don't skimp, and reapply frequently.
Try to maintain any parts of your routine that are possible. For example, if you usually read a few books together and then have a snack before bed, there's no reason not to keep these activities up while camping. Doing so can help keep baby content and as well rested as possible, which means that the rest of the day will be more fun for everyone.