What storage wars and the other shows don't tell you is that it costs money to get things appraised, in most cases. The way I like to appraise things is to make friends with local auctioneers. Maybe list a few items in their auctions to get the business relationship going. This way, when you get something needing an appraisal, you can always ask their opinion. Some items that you get an opinion on, you may want to list in an auction anyway..
I think, however, there is enough information online to get enough of an idea to put a price on things. In my shop, I have a big sign that says "We Welcome All Offers" because I know that I may be shooting the moon on some items. If someone has more knowledge than me, and can educate me on an item or genre, I may just accept their offer!
A good example of this is the book "The Little Prince". I have a first edition copy with mistranslations. The book was originally written in French and translated to English with errors. I have one of these priced at $100. However someone came into the shop who is a book guy. He said that while yes, this is a first edition with mistranslations, the books that are worth much more have a different color cover. Mine is a cream, the salmon covers go for much more. He pulled out his iPad and showed me examples. He said that my book, in fair condition brings $40. My book he said was better than that. So he offered me $60 and I took it.