Isabel, what a great list of takeaways! So many of them will make you look fab no matter in what outfit you'll be wearing, since they are more in the personal grooming/polish category.
I think you are exactly right to take a makeup lesson. I just did that recently. I never wore much makeup because I was self-conscious of looking "made up." I recently went to a spa and booked an appointment with the esthetician, who is also a makeup artist, and learned how to do it properly. Now I am no longer afraid! Instead, I practice and play around and make it fun.
I will say too that in my case I discovered that a good makeup application can help distract people from less-than-perfect hair. When I came home from my makeup makeover, I said to myself, "My face looks so good, I won't ever have to be concerned about my hair again!"
Deb once recommended Lisa Eldridge's site for makeup tutorials. I would highly recommend it too! Once you get the basic application down, you can do some other looks: basic daytime, sun-kissed, bold lip, etc. That's when it starts to get really fun!
http://www.lisaeldridge.com/video/
For years I wore only neutrals too, and I am just now getting into color. So you're not the only one! Just go slow and try out different colors bit by bit and see what you like. I find that the season is of paramount importance as to what colors I am attracted to. So you might find your likes and dislikes changing in this area as the seasons change.