This is the big question for most, "am I ready?" Unless you are a complete neophyte, the answer is probably "yes". Wall climbing has a unique way of yielding to various skill levels. For example, the Nose on El Capitan can go at 5.6 A1, or 5.10 A1, or all free in the high 5.13 range. So, are you ready? Yes.
Wall climbing is rarely about big skill and great shape. This is another plus in your favor. Wall climbing is systems and tenacity. With a basic knowledge of how to free climb, a good idea of how moving within the aid system works, and a bulldog determination to reach the summit, you will. So, in the most basic terms, here's what I recommend for somebody thinking about doing a first wall.
1. Be in good shape, especially in the cardiovascular area. Wall climbing is less about climbing and more about being able to bust your hump all day long. Most wall days are about 12 hours of toil. It is a lot like working on a shipping dock, except there is no floor.
2. Have strong legs. Hauling and Jumaring is just like going up flights of stairs. If you get a leg shake carrying in the groceries at home, do some leg work. Any good program of bike riding, talus hiking, or gym work will help you out in this area.
3. Have strong hands and forearms. Hanging on Jumars all day will bake you. Better technique will help you here, but on your first wall you will be gripping these units so tight that if the handles were coal, they might turn into diamonds. Cramping is also a big problem here. Always try to hang on your Jumars from the daisy chain to your waist rather than your hands and arms. A smooth technique here will save you tons of grief in the form of sore hands, cramps, and power failure.
4. Be confident. Break the wall down into small chunks rather than looking at it as a huge ordeal. Plan out your bivies and then hit the marks. Each day is a new day, and even if you rolled into the bivy at midnight the previous night, hit your mark today and then keep going. Think of each day as a mini wall. These little victories will keep you going.
5. Remember, it is supposed to be fun. Don't pick a partner that is an anus. The pressure that is put on any team will bring weird vibes and outright yelling to the surface. There is an old adage that "put a man on a wall and you'll see what kind of man you've got". Very true. Maintain an even keel. Everyone up there is trying to do their best. Berating your partner is a fools game. Work together as a team, not some macho solo act. You ain't Patton.