I would advise that you take it slowly and start with your primary doc. Tell them your goals and ask for a blood panel to show your existing nutrition levels. They can't test for all of them, but they can test for the ones that are commonly deficient (D & B12, for example), and they will check blood sugars, cholesterol, etc. for other dietary imbalances.
With that info you can then begin to do some intelligent research on what would be beneficial to you. Don't start with a health food store or the internet for a shopping list. This will have you suddenly spending $100's/month for stuff you may not need, and if any of it causes problems for you, you won't know which supplement did it.
So find out if you actually have any deficiencies or imbalances and address those first. If your tests show that you need supplementation, no doubt the folks here can guide you to the kinds, brands, etc. that have worked for them. If all your tests are normal, you are probably just as well off with a good multivitamin designed for your age/gender.
"The only thing that makes me depressed, Doc, is not getting any answers from you."