1- Go to your Facebook page
2- Then go to the post you want to boost. You will see a blue "boost the publication" button (i don't know the exact name in english)
3 - Click on it. A windows open with, on your right, what will look like your publication on a computer, mobile, etc.
4 - The left column is the most important. Here, you can choose to target your audience.
5 - On the audience section, select the first option (people chosen within this target)
6 - Target the age range and gender corresponding to your Google Analytics data, in my case women from 25-34 years. You can also select a special place (this could be very interesting. I just come up with a new idea for this)
7 - I just realize right now i forgot to set up criteria in my two first facebook Boost. It's really a shame, as a too large audience isn't very good. Next time i will do better. Now that i know, choose to target with demographic data, hobbies, etc. You can really target very closely your audience here.
Make sure your audience isn't too small neither.
Then select how much you want to spent on the length of your boost.
8 - When you're done clic on save and then Boost.
9 - You will received an email to tell you when your Boost is ready.
10 - You wan then check your data from this boost.
That's it. This was my first one tutorial. I hope you learned a thing or two.
Please, click on the green like button if you liked it :-)
Sylvain