“Nobs” is holding a jack of the same suit as the upcard. “Heels” is when you score 2 for turning up a jack.
There’s a lot of strategy in cribbage, and I don’t even know where to start. A lot of it is percentage play, don’t pass cards that could potentially end up in runs or 15s, watch your lead, try to figure out what your opponent is doing (Is he leading a 10 waiting for you to throw a five on top, only to pair it? Or is he hoping you throw out another 10 for pair and he’ll score 6 for pair royal (three of a kind) and then perhaps another 1 for “Go” or 2 for 31 if he has the ace and you can’t move (likely)).
Watch your opponents hand and try to guess, as the cards come out, what he is likely to be holding. Pegging points are often what separates decent players from very good ones. Don’t become careless with your pegging. If somebody leads a 10, you can usually bet that his hand contains either: a 5, another 10, nothing but 10-point cards, probably in a double run (e.g. 10-J-J-Q). Of course, when you start playing people who know your strategy intimately, they might mix it up just to keep you on your toes, but most of the time, that’s what a lead of 10 means. Use that information to your advantage.
As for discards, the general rule is to throw out what will help yourself and least likely to help your opponent. Throwing points into your own crib is often a good idea, touching cards is good, pairs and 15s are okay, etc… For the opponent, generally don’t throw out points (unless you have good reason, and “gifts in crib” are occasionally sound plays), try not to throw out touching cards (6-7 for instance, as they lead to big double or triple runs) or cards that are even two removed from each other. Don’t worry about taking suit into consideration for any of these–flushes in the crib are pretty rare, and even flushes in hand are often not worth the trouble. It’s usually better to go for the double runs that give you lots of “outs” to make.
Once you get comfortable with the crib and pegging, you’ll need to learn how to control the tempo of the game. You don’t always want to go for maximizing your hand score. Sometimes, you want to minimize the opponent’s hand score. Remember, one rule that vitally alters strategy is the fact the opponent always counts first, so if he makes his 120 before you do, it doesn’t matter if you would have had the highest score. Always keep that in mind.
The best resource I know of for these sorts of things is http://www.cribbageforum.com. Have a look around there and you should be able to find something that will help you.