How can I educate myself about existing and upcoming lines of bags?

I agree, that chanel website is not so great. I try and go to the boutique as often as I can to see the bags. Fashion magazines are also very helpful, but I find that right here on this forum, fellow pf'ers post pictures of new stuff that didn't come out yet. Check this forum a lot and you'll see and also learn a lot too.
Ask the ladies here... this is a huge problem for Chanel. You can ask at your local boutique, but I know many of the members here are a huge help (I get help from them about it ALL the time!!)
I am hooked--to Chanel bags (now) and this site. I actually only bought my first Chanel 2 weeks ago (a Coco Cabas) and then last week another (diamond shine flap in bordeaux). I am already looking for my next one--although it will have to be a while!
Yes, the website is useless. I actually learned more purse names and styles from sites selling FAKES than the actual Chanel website.

But I def. learned the MOST from the reference library right here on tPF. Now I have a Chanel hard-on like crazy.:Push:
This forum is the BEST place for information on upcoming lines and exisiting bags. As you purchase, your SA should invite you to the pre-season trunk shows. There you will see IRL the upcoming bags which you can pre-order.
However, most of the girls here know way more info about the bags, leathers/materials, season, where to find it, etc. AND everyone here is very friendly and loves to help each other out.
I totally agree!! I've said this before on other threads...going to the trunk shows is so not only get to see everything for the upcoming season straight off the runway, you can meet the chanel rep and ask as many questions as you helps tons
You can also try establishing a good relationship with your SA. My SA calls me to run through the new catalogues with her everytime she finishes training for the new collection.