BARUCHAS

Question

I get very confused with not making baruchas versus the possibility of barchas v'atallah. For instance, if I would eat a variety of the same thing, say green and red grapes or mixed chocolates, if I make a barucha over the green grape, isthe red covered? If I eat a chocolate covered peanut and then take a chocolate covered cashew, or get a candy I like more than the peanut, is another barucha needed? After a meal without bread doe s glasds of water need a new barucha if I did not have the kavanna to cover everythibng with my first shehakol? My review of baruchas makes it seem like a complicated issue, are there simple rules that could make it foolproof? Thanks.