The first thing is, to educate yourself about the area or areas you want to collect in, and not just read one book, but do it in-depth, become a scholar. Otherwise, expect to get burned if you do it alone and with limited education about what you are interested in. It is when a “collector” gets lazy or when they find that they think they know enough that they will get caught by a shyster. Ego gets in the way much more than you think it does, “because I have studied enough already!” There is really never “enough”, because the fakers and fraudsters are aways trying to stay one step ahead of the art historians and especially the uneducated public. The one thing that you must be exceptionally careful about and understand is that this industry has more conmen/conwomen in it than there are honest people! I hate to say it, but it is true, and you must get it – so only work with people who have stellar reputations and/or have been recommended to you by people you truly know and trust. Be careful every time you buy!
At the beginning you really should use a consultant to work with OTHER than the dealer themselves – dealers have a distinct interest – their own, no matter how friendly and helpful they are. Here is a small example of this, I had a friend refer his father-in-law to me because he wanted to start collecting art and had thought he found a little gold mine in a shop north of the Twin Cities. My friend convinced him to consult with me, and he did. Of the 6 “Fine Art Prints”, 2 x Picasso, 2 x Chagall and 2 x Warhol, all moderate sized, 3 were fake and he did not want to spend the money on the Warhols to have them authenticated appropriately, to which I told him I would have to err on the side of them being forgeries based on the fact that I had two Warhol experts both say they thought they were fakes! Only 1 Picasso was real! I saved him over $14,000.00 USD because he knew enough to know he needed help because he was new to collecting! A good consultant will be happy to teach you and help you head off on your own way. This in turn will allow you to create trust in them so that in the future, if you are not sure, you will always have them to contact and work with again – for which they will be very happy to have the repeat business and trust. Good luck.