Hey Morningrider, congrats on the new bike and getting back into cycling. Lots of great advice from the folks here, especially the list from "practical" aside from the mirror which I generally think is more dangerous than helpful. Learn to look over your shoulder! I got numb wrists when I started riding again and no one seems to have mentioned this: Make sure your wrists are not bent when you are in your riding position. They should be as straight as they are when your arms are just hanging limp by your sides – not flexed at all. If your wrists are bent when your on the bike then you should adjust your handlebar grips rotation and your controls (shifters, brake levers) so that your wrists aren't flexed. There is a nerve in there that will not be happy otherwise and can cause that numbness. And don't lock your elbows – keep them slightly bent so they can help absorb shocks.
I agree on the gel padded gloves. They help smooth out the bumps in the road, but equally as importantly they improve your grip on the handlebars which is an important safety benefit. Go with fingerless gloves until the weather gets too cold. Also agree on the ergonomic grips and addition of bar ends which will give you additional positions for your hands when they start to get tired. You will get used to it over time, but in the meantime you can always stop and shake out the numbness for a few moments – get the blood flowing again. Make sure you're not putting too much of your weight on your hands and wrists, too. Most of all, keep riding and enjoy it!