Also, climbing outside, especially trad routes, you will find there are fewer holds marked with coloured tape.
Carying a rack of gear can make you feel awkward and unbalanced when trad climbing, at first. Practice in the gym by duct taping a couple of phone books to a webbing sling and wearing that over your shoulder as you climb.
Prepare for hand jamming now by belt sanding the backs of your hands to a cherry red colour.
Loudly denounce sport and gym climbers as inferior. This will help you feel trad even before you place your first gear.
Seriously though, rock climbing outside is not difficult. Practie building anchors now. When you go outside, start by top roping. Graduate to leading bolted routes that you are familiar with, then move to trad, then slowly increase your grades.