I have over 100k followers, now what?

Well one way to find out is to get them to OPT-IN list, then create a survey on surveymonkey.com or similar service and ask them what they like. simple.

You already know your demographic so now search clickbank for a top product in the niche and extend your research to pinpoint Profitable keywords. I use Keyword Planner + Google Trends + Keyword Spy(In This Order).

Keyword Planner- enter website of 1st page Google site result for a female niche targeted Clickbank product. This will return a list of keywords that site is targeting which are evidently good because they rank well for them.

Google Trends- Paste those keywords into search bar and look at chart to see if trends are up or steady on keyword and also what region/country is most interested in keyword. Helps with targeting your campaign better from the start.

Keyword Spy- They have a paid platform, however the free sign up is good enough to me. You can now paste 1st page domain or your keyword(s) that passed in keyword planner(low or medium competition with 1000 or more searches) and Google Trends(Rising or steady trends with regional insights on searches) and search for relevant keywords or competiton that have already profitable ads that you can tweak for your own.This is if you are running PPC for traffic to affiliate offer.

For a free way after research above just search in all of your different social media channels for the profitable keywords you found to target your prospects. At least you'll know that you are working with profitable keywords straight out to market with. Therefore cutting out time guessing.

Hope I could help.

There are so many ways you can exploit your particular demographic. I am presuming you are male, so forgive me if I am wrong, but ask your sisters, wife, girl friend, daughters, female friends - and yes, as suggested above run a survey on SurveyMonkey, but make sure you think through the questions properly so the answers will actually provide what you are looking for.

Could you explain what you mean "from ads?"

if all them are real and Active ! You will make A Big $$$ From this page

I advice you to search topics from Blackhatworld !

targetting young girls with fashion tips, fashion wears, beauty and health related products,
would be a great idea, but you need to build a list to make full use.

Find out which keywords are highly-used by teen girls when they perform Google searches. However, if you want a practical answer to your question, of course, you can try engaging in a business related to fashion – clothes, accessories, shoes and more. Just do your best in making your advertisements appear attractive to your target market.

Give them an offer stating that whatever beauty product you use, get more likes on your photos .. Beauty is the secret ingredient.

Anything that is music related---Bieber, One Direction, Justice, the kids will bug mom and dad to for the credit card. Trust me I know 1st Hand!!

JSacks,

I'm more interested in learning how you managed to get that much of a following. They are all real humans, correct and not fake followers coming from fake accounts or bot traffic ?
Mmm. If I can have a look at your technique then I can always see if I can build an automation tool or not to rinse and repeat the technique hours upon hours at super high speed.
You can always write an ebook and sell it that teaches how you did it. And, you can always ask your followers what they'd like to see next after following you.
If I were you, I'd build a tool that uses the same technique to generate followers and then give the tool away as a contest win. This might attract a lot of my followers signing-up to another site of mine just to play the contest and then I'd sell that site to a competition and make money that way. At the end, I can always sell the automation tool to the losers of the contest. They might be interested to learn my follower gathering techniques from the automation tool.

If you really want a profitable niche for young females, I suggest you conduct a survey. Ask teenager females as to what they are interested about. Through that, you will be able to get the most profitable kind of niche that would surely be a big hit to your subscribers - who are teenager females.

HI

Promoting an affiliate sounds like a very good ideea.Try to do a google search for what teenagers go crazy theese days

Well then I think the interest will be more probably about fashion, clothing, accessories, beauty products. Or just to make search, make a research about it on the web.

Just promote products & services that are related to the channel they followed you on.

Consider doing a TeeSpring Campaign as well.

If this is in a good niche, create a private group for them. Then after a while try converting that private group into paying members by setting up a membership site.

100K is huge! You should do well with fashion and clothing.

You should try and push affiliate products that are in your niche. Perhaps even go as far as using Amazon Associates.

Create a video about how to earn money online easily by your experience and then you can sell it by your website. Or join with a good affiliate program and promote your affiliate link on your website. Or you can sell traffic to others.

Girls that age love games and are always online. Maybe something related to girl games. There are many affiliate programs for that.