Hello, I just created a follower and I have 4 problems with her.
1: Even though I exported the face gen data her skin looks dark in her face.
2: She appears to be my follower even if I tell her "it's time for us to part ways", but even if she does, she is not following me.
3: I can't trade items with her, when I tell her to trade items, the item window doesn't appear or anything.
4: I created her in another mod I had downloaded because I wanted to include that mod in her accessories (glasses, etc...), but when I put the glasses in her inventory she doesn't wear them for some reason.
Could anyone please tell me how to solve this problems?
Thank you very much in advance.

1. press alt + F4 with your follower selected in the CK to generate the facegen files.
2. You need to ensure that she has a followin package equipped. This is usually done by a reference alias. That alias needs to be released in the resulting script in the "it's time to part ways" dialog.
3. I suppose you added the openinventory() funcion on her, in the resulting script, but she need to be set as a player teammate for this to work. So, either use the setplayerteammate() funciton on her (in the dialog where you recruit her) or instead of openinventory() use openinventory(true) -better if you do both things-
4. If you use the setplayerteammate() function on her (usually in the dialog where you recruit her), she will put the best equipment for each body slot the next time a cell transition happens.

Thank you for your answer, however, there are some things I still don't really understand...
1: I already did that but it didn't work...
2: How to equip a following package? What is a reference alias? could you please explain this point again... I don't really understand what you mean, I'm sorry, I'm new to this so I don't really know what all these things mean.
3: do I need to 3 open the console and write things there?? I actually followed this guide to create my follower: http://j-u-i-c-e.hubpages.com/hub/Hot-to-Turn-Your-Skyrim-Character-into-a-Follower
4: Umm... I hope she does so...

Amgepo meant to say F4 for the face gen thing. In certain lights it may still appear darker, I've found - but nothing like what happens if you don't export the data.

Umm... yes I already did Control + F4... but it still doesn't work, not even outside...

Could someone please help me??

First, you might want to check out some of the other follower packages. These are the ones I watched before I made my follower:http://www.creationkit.com/Video_Tutorials

Hopefully some answers that will help you
2. You don't "equip" an AI Package, you add it to the AI Package Stack by opening the Actor dialog and clicking on the AI Package tab. There you will see the list of AI Packages for your actor. Right-click in the listview and select "Add". Adjust the ranking accordingly as the package at the top gets first priority.
3. No, no console commands are required. I only use console commands for help when testing & debugging my mod, not as part of the mod itself.