I am 47 and I have dated younger guys but they have all approached me, not vice versa.
I would never initiate flirting with a younger guy for several reasons. First, I respect the fact that most people are going to date people their age. Second, I am only interested in a relationship, and many young guys are just looking for "fun" with an older woman, not anything more than that.
So, if you do initiate contact I would say we flirt like any woman or girl would. Light, fun conversation and eye contact. The only part that could get tricky is I flirt with guys I have no interest in dating. In other words, a guy could approach me who is too young, not my type or just otherwise not a good match, but I am not going to be rude. I will laugh and have fun talking to the guy if he starts a conversation, but that does not mean I would go out with him.
At 32 I'm less shy but still flirt just as much but I'm the same with everyone if there's a connection. I used to be called a flirt as an insult by some girls because were intimidated but really I had no idea I was being one I think if I was aware on some occasions it was a front because of how nervous and shy I was. I wasn't girlie and giggly nor was I blunt and forward I always thought I was just being chatty and fun *shrug* Now though I am more aware of what I am doing and what I want although I may not be as outrageously fun anymore (guys would be attracted to my energy and craziness but once they got to know me they found even at 23 I liked to be home before midnight to get sleep for work the next morning - now though I barely sleep til 4am but I'm going waaay offtrack here lol)
I've not had great experience with guys or much to be honest. I'm a good friend to have to boost ego and for very honest opinions I usually end up being the friend that helps others (guys and girls) find their next partner lol when a guy likes me & if quite forward I feel more intimidated and unsure of myself. I had a 25 year old hit on me recently but because I didn't initiate it or was caught unawares I almost panicked lol. As much as a compliment it was I felt I was being a craddle snatcher even though mentally I'm still 23 and physically I look 25 I can't help but worry.
Anyway *ahem* sorry for going offtrack I'd say flirting would be the same, smile, eye contact, a touch of the arm, double entendres, blushing ect etc ect.
Some older women may also be incredibly forward feeling now they are older what have they got to lose and they know what they like and sod it and will blatantly say outright they like you. If you don't like it mind just be polite and make excuses though just like you would a younger model we all still have feelings however much bolder we might be feeling.
i'm only 24, but comparing myself as I am now to what I was, say 5 years ago, I am a lot more aware of what I want, and I'm more apt to just go after it. so I would assume that in 10 years, I will be even more aware of what I want, and if I am interested in a guy enough to approach him, there won't be any mistaking my interest for him.