I was new to the table and I bought in for $200.
It was literally the 5th hand:
1). Preflop:
2). Flop:
3). Turn:
4). River:
They both had a bit more than $200 each, I could of gotten away from it but can I get some opinions on what I should of done better ?
Pre-flop, with six limpers coming around to me in the big blind (and no information about the personalities at the table), I wouldn't be too thrilled with any pocket pair. With a premium pair, I'd raise for sure, but I think with sevens, you made the right move by calling. If you hit a set, great; if not, you lost nothing.
The flop was great for you. You're best for sure; your sevens beat anything besides pocket kings, and anyone with kings should've raised pre-flop. Good time to build the pot. The only thing you might be worried about if you're really paranoid/tight is someone holding 56, just because of the sheer number of players. They'd have eight outs to a straight, which means about a 1/3 chance of getting there, which means mathematically it's correct for them to call a bet of up to half the pot. At this point, the pot is $14, so your $5 bet was not terrible, but I would've gone higher.
The turn is more worrisome. It's good that most of your opponents got out of the way, but now a lot of draws have opened up for hands that people like to limp and call small bets with (e.g. AQ, QJ). You are almost certainly still best (set of tens over your set of sevens is barely worth considering) but you have to make a bet large enough to get drawing hands to fold. At this point, the pot is $29. The same math as before applies: eight outs for anyone on an open-ender draw (of which there are now two), which means 1/6 chance of hitting the river, which means it's safe to call up to 20% of the pot. Your $15 is a mathematically correct, but not particularly aggressive, bet here. Something bigger would let you either take the pot down immediately for guaranteed profit, or (more often than not) increase your winnings at showdown.
The river has got to be scary for you. QJ just made it, and it's definitely in range for someone who likes to limp and call small bets. It's a bit scary that UTG bets out at you after being passive all hand long. You obviously can't fold with your set, but raising is dangerous, especially with someone else to act behind you. Calling was the right move there.
The villain bet is even worse; a big raise like that, especially considering that UTG already showed strength, plus the size of the pot, should be setting off alarm bells. (As vlzvl pointed out, you don't mention most suits. I'm assuming there are no flush draws.) It's hard to know exactly what villain has. It might not be the straight; you were in the big blind and you didn't play very aggressively, so you could easily have A7 or K4 (in his mind), so he might think he's good with AT or KT. But he's definitely representing the winner, and it's certainly in his range.
I think you would have been better off limiting the damage (i.e. folding), tightening up, getting some reads on your tablemates and waiting for the next good opportunity. So far, you've only put $47 into the pot, and $2 of that was the blind. You can still play effectively at that table with $153, but not $53. In that spot, $100 is a lot to pay to find out what villain is holding. Big bluffs are more common in stories than reality, and you'll be able to get information about him for cheaper later (or free, if you watch him carefully against someone else).
With 7's pre-flop, I definitely would not have limped if I were going to play that hand at all.
7's don't represent a "bad" pre-flop hand, but they certainly don't represent a great one, either, and your lack of a raise allowed six callers to potentially hit an over-pair, straight/draw, flush/draw, etc... on the flop.
If you're going to play a marginal pair pre-flop, I think it's important to protect that marginal pair by weeding some of those other players out with a raise. You don't want to let those guys see the flop for only the cost of the BB and hit an over-pair on you. Not only will raising there represent a premium hand, allowing you to bluff should any paint hit the board on the flop (especially if you hadn't hit your set), it would've also allowed you to bully any would-be pot-stealers if they'd limped and hit the high-pair, but with a poor kicker. For example:
If someone had hit that king on the flop but they knew they had a weak kicker, your pre-flop raise could've represented that you also had a king, but with a better kicker. They may have even thought you had 2 kings in the hole. They may have figured you for AK, or KQ. Either way, if they're staring at K5 and realizing their kicker is actually coming from the board, and not their hole cards after you've represented something premium pre-flop (masking your true hand, the 7's), at the very least you're putting a seed of doubt in their mind, making them worry that their weak kicker wouldn't sustain them if it came down to a heads up situation. You don't want to lose a hand because you were afraid to protect your hole cards.
Since I don't know what the blinds were after the flop hit (and therefore, what the overall value of the pot was at that time), consider this an observation more than a critique--
Once you saw the flop, realized you'd hit your set and only bet $5 (after limping pre-flop) you priced the other players in, increased the risk you'd get sucked-out on, and undervalued your hand while minimizing potential return. I understand that you were trying to set the hook and keep these guys in the hand, but it's important to get some added value for your set. Premium hands don't come around often enough for any of us (I'm sure we'd all agree) and when we see them, the point is to get paid-off. You're lucky you forced three players out of the remaining six to fold with that play. If all six had called your $5, that's 5 players that could've been chasing open-ended straight (with the 4 and 7 on the board) which would dominate your set.
However, if the turn were another king, the person I mentioned previously who hit a pair of kings with a poor kicker on the flop would then have a set of kings, but you'd then have a full house, potentially increasing your return.
It's a risk/reward thing, but if anyone had had "5 6" in the hole, the chances of hitting an open-ended straight after that is 5-to-1, which is much higher than the chance you'd hit a full-house. You need to leverage the odds as much as possible, and if you're going to string players along, encouraging them to hit something on the turn that is still weaker than your hand, you need to be damn-sure that you already have the nuts, have an extremely high probability of hitting the nuts on the turn/river, or have something that may not be the nuts, but is the second best thing.
In conclusion: I personally believe (and I'm almost positive Doyle mentioned this in "Super System 2," though I'm not positive on that) if you have a marginal pair pre-flop and are going to play it, you need to raise to represent something big, earning you leverage for continuation-betting on the flop, turn, and river. Further, if your'e lucky enough to hit a set on that marginal-pair when the flop hits, you need to protect that set by betting something you can be confident will weed out the stragglers who are chasing something on the back-end that will dominate you.
You're lucky to have won the hand (you DID win the hand, right? or am I reading that wrong?) because anyone could've hit a straight given how many folks you let come with you, and because you didn't protect your hand by increasing its perceived value, you left the outcome up to chance, and you should limit that as much as possible with smart play and skill.
