Anna Sparky's Mom had some very good suggestions.
I think its important to remember that you have reached a time in your life where you already have pleased everyone else, and now its time to please yourself.
Hair -- NO grays. It doesnt matter what color, light or dark, but gray has got to go. I suggest getting it done by a professional (it makes a WORLD of difference) and also try getting a new cut. The cut should be stylish but maintainable. If you are a short haired person, for example, go for something like Kate Gosselin/Victoria Beckham instead of something short and perm-y.
Makeup -- This is where it gets tricky. Depending on the condition of your skin, certain things may not work as well. But the idea is to get an even, bright complexion. This may take more than one step. I'm in my 20's and to get my face looking how I want it, I use concealer, foundation, blush, and a highlighter. Thats 4 products JUST for prepping my canvas. The point is... there is no shame in taking time to do your face. And that your makeup kit is bigger than most drag-queens. Once you're practiced, it doesnt take much time, I promise.
Makeup (cont) -
Skin Must Have: Concealer, blush, cheek highlighter, fan brush. Take the fan brush in the highlighter and smile... draw a C shape from your cheek apple, around the outer corner of your eye and up to the mid brow. This will brighten your eye area immensely.
Eyes Must Have: Cream Liner (try Smashbox), GREAT mascara (Try Bourjois Volume Clubbing Mascara, or Too Faced Lash Injection). The cream liner will go on smoother than a pencil and with practice you can give your eyes more definition. A good mascara will give you bigger lashes without the clumpy-Whatever-Happened-To-Baby-Jane crazy look.
Lips Must Have: This varies from person to person. If you have thinner lips, use a lipliner and try plumping lipstick in the same color. If you are pretty confident about the shape and definition of your lips, good! You can pretty much do anything.
Clothing:
You are trying to look younger, not like you're in your 20's though. That would be silly. Because you are a mature, sophisticated woman, you will want to focus on specific shapes and cuts of clothing. This is when you want to start thinking tailored. Stick to the rule - dress for your body shape. Pick up a copy of Marie Claire... they always have good, classic fashion examples in there, and the age range is really 25+ which is in your range.
You also want to take care of your body... but do it in a fun way. Yoga, salsa dancing, pole dancing... just eat right and exercise, blah blah blah. But again.. if you're over 50, its time to start pleasing yourself :)
PS: I know its a little personal, but if you wanted to post a link to your picture, I'm sure that would be more helpful than us trying to do it blind. I hope this helps you!!