I'm rather new like you Ron, I've been playing on and off for 3 years, but when i say on and off, I mean a bunch of freerolls
(which i've done good in) and then a few months of no poker =P.
Now that I'm getting serious, I realize that you and I share the same problem: Just being worried about someone out drawing us or over playing a hand, and definitely how to play late in the tournament that's gone on for 2-4 hours already. There have been some great points: First and foremost people tend to clam up big time as the cut off approaches, and that's a great time to steal blinds with suited connectors, face card and a good kicker, and even high, unsuited connectors (which really to me is 10-9 in a good position, or J10). This strategy helped me place 13th in a tournament with 3,000 starting people (and that's when they stopped the tournament because the top 50 advanced to the weekly final, which i got 53/1000 in). Now, Ive done well in a few tournaments, and poorly in more but I must say that in a MTT tournament, with a lot of people, luck does not carry you to the final 10-20%, so I must be doing something okay (or there is a god with a sense of humor =P)
Most of the times I do a shift in gears from blind stealing to tight and then somewhere in between. The thing about stealing is you cannot be remotely predictable about it because late in a tournament there is a good chance there are a few good people at your table. If you always steal in certain positions, while it's a smart Idea, it can also lead to people reraising. You can minimize this, in my opinion (which is probably not worth much seeing as I'm just a novice), by using the experienced person's experience against them. They know when it's good to blind steal, and thus are more likely to pick up on it when you do it the 'right' way. However, every now and then blind stealing from, say, mid position, or even 3rd position, helps you get away with more steals. The experienced player on the button was thinking about stealing, but thinks that since your raising in a weaker position, you're most likely not blind stealing, but actually have a hand and are trying to double up or knock someone down with it. Unless his hand is good, theres a good chance you wont get a call or re-raise from them and take down a pot. Of course this has the danger of the blinds having something, but that's a risk you'll play when blind stealing in most positions pre-flop. Of course this all depends on the image you've presented, and the other person(s) as well. The odds in the long run of blind stealing from early to late position are probably bad, but if you throw it in there every now and then (maybe if your blind steal attempt earlier was ruined?) it has the advantage of being unpredictable and misread.
I like to steal post flop, because closer to the cutoff/final table most people wont call you even if they have mid to top pair. Hell, if there's even a straight or flush opportunity (or even a draw opportunity for any great hand!) on the board, i've seen a lot of people get out of the way quickly even if they bet like they had a good pair. There are still people at this stage who dont want to loose to a bad beat, or dont want to risk their stack against someone who it seems has a flush/straight or has one more card to get it. I've noticed this from a bit over half the people i've gone against at this point. Afterwards the play is all about being unpredictable and playing a style that'll counteract your opponents tendencies.
Mostly it's all about reading your opponents. While im not very experienced, i must back up the assertion that 15 hands is no where close to being reliable enough to have a read on people in the early stages. Many times i've had little information on people because I've never seen a hand of their's after 20-30 hands, even more. They could be playing rock solid and always have a hand, or bluffing half the time, but unless I see a hand of their's it's hard to get good reads (that I know of, i could be wrong). Unless of course they're betting like they have a great hand 50-70 percent of the time, then you know somethings fishy Finally, it's hard to get a read on all your opponents after 15 hands because, in MTT's (especially the large one's i've played in) people in the beginning phases go out quick, and after 15 hands either i've got 4 new people at my table, or I'm moved to a new table with 9 other people I dont know at all. And while you might have a read on 2-3 people, those other people are wild cards, and when trying to steal blinds or be aggressive, chances are you'll be playing against people who you haven't figured out well enough yet.
If I can say one thing from experience, is that I am much more successful if, during the early stages, I play the survival game. Play mid pair or higher, and premium hands like AK and KQ (both suited) and possibly QJ suited (all depends on position, although the latter tends to cause me more trouble than it seems to be worth =P) I get some nice wins from the BB because I can steal pots i miss with ease depending on how many people are left since people realize that you could have limped in on the BB with anything (I promptly get out if reraise, then I know someone really did have something)
Guess my point after this long, and probably incorrect, post is to get to know your table before you start loosening up. Then you know you can pot steal from mid position because the only people after you right now to bet are all tight players, and when to call people who are stealing because you know your odds of having them beat pre-flop are quite nice.
of course this is all from my experience, which is limited compared to most on here and you can take or leave it as it is. I dont want people to say 'you're a moron blah blah blah' or say 'wow i laughed when i read this' if you disagree please tell me, I have much to learn about poker and would love to improve my game as well.