I'm not saying you can't steal early on, I'm not saying you can't raise weak late position limpers from the button and suchlike, but generally when you play a hand in the early stages you want either (a) a very strong hand or (b) huge pot odds (5 players limp, scr888 you're in the SB with 97s, that sort of thing). You will find that your big hands will often get paid off and you don't need to be throwing chips about early on.
As the blinds get larger, a lot of bad players tend to tighten up, because what was once 20 chip limps or 60 chip raises are now 100/300 limps/raises, and are a large portion of their stack. This is pretty much the opposite of effective strategy, as of course given that the blinds are larger and larger relative to stacks, they're more worth winning.
Be careful and pay attention to stack sizes on the bubble. In 9-player SNGs there is a nearly 200% ROI 'swing' between 4th and 3rd, meaning that if you can scrape into the money, it's worth it. This is unlike big MTTs - although they have a large ROI swing between bubbling and scraping into the money, they have a huge ROI swing between scraping into the money and final tabling. While in MTTs chip accumulation should generally be your aim on the bubble, in an SNG survival should be your main aim. If you and another guy have 4k chips on the bubble at 100/200 blinds and he shoves with a guy with 300 chips still to act, your QQ should become a trivially easy fold.
Playing lower buying SNGs won't harm you greatly. The transition isn't as marked as the transition through cash game levels. Regardless of the buying, effective SNG strategy remains very similar - tight early on, abuse the bubble or survive it depending on stacks, learn optimal push. fold strategy. Sure there are differences - you can get away with playing a little looser early on in fish-filled lower buying games as you can often stack or cripple someone with your AJ when you both flop TP and you get called down by A3s or something (whereas if you raise AJ in EP in a higher buying game, most people's calling/reraising ranges absolutely crush you), you should tighten up a little more on the bubbles of lower buying games as people will call you with generally wider ranges, but the difference isn't huge.
If you really want to win without losing first, read as much as possible with very little play sprinkled in. Finishing both Harrington books and Moshman's SnG book will be better for you bottom line that throwing away your "tuition money".
You should generally play tighter in the early stages and then begin playing hands like Ax in the mid stages depending on your position in the tournament, you stack size relative to the blinds, and your table position. Obviously, you won't have to take as many calculated risks if you have a decent chip stack relative to the blinds. As the blinds begin to chip away at your stack, then you want to begin to open up and play more hands like Ax for cheap pre-flop hoping that you can connect on the flop.
In the beginning stages, you can get away with playing speculative hands more than you would be able to in the middle stages. In mid to late position in an unopened pot, you can limp in with hands like 9-10s and play for cheap to see the flop. if you happen to connect significantly on the flop, then you can begin either trying to steal the pot or trying to build the pot. but you don't want to be making calls with these hands, and unless no one before you enter the pot, you don't want to be making raises with these types of hands preflop because you risk becoming pot committed on your continuation bet if you happen to get called.
My tip for beginners: Seems to me beginners are taught to think about starting hands when thinking about the position is by far the more fundamental lesson. Though there are good arguments against it, I think logging a lot of hands in free-rolls, play-money games and home "for fun" games will help you get some of the mechanics of the game without devastating your wallet.
The majority of beginners think it is o.k. to limp in for only 20 chips with your A6 in the early stages. If your ace hits it could be deadly and potentially end your tournament when you get beat by A9. This is why you play your premium hands in the beginning (raise them) such as AK, so when you're playing a weak player who is holding the Ax he will dump his chips to you thinking "I have top pair!" Play "tight/cautious" in the beginning as Moshman says and begin to loosen your range when the blinds go up to steal some blinds, just as players who play like you initially tighten up and fold to your raises.
Speculative hands such as 9 10s can be valuable to play in low blinds if you are in late position and have the right odds to call, i.e., a few limpers in front of you, which could possibly turn into a monster hand. Fight the urge to limp with that Ax in early position and fold it, it will cost you money in the long run.
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