Try to avoid the domainer blogs as most of them blog with vested interest and mostly promote the fields that they have invested in. You will most likely hear things like 3d is the next big thing, NFC is dead etc. Don't fall for their trap. Also most of them are in the field for long and have a good portfolio they could aquire for low price. So you may not be able to replicate their success. But surely its good to read as some of them do share their mistakes.
It is better to start with domain market places like sedo, godaddy auctions etc and see what names are selling and for what price.
Or even visit the Namepros market place to check what are the general reseller price (though take these sale prices with a grain of salt).