Stealing in the later stages: How to do it right?(6$)

[illph]

I know this sounds kind of general but is there a secret to successful blind stealing?
Lately I'm taking a lot of 5th, 4th and 3th places because I get caught trying to steal the blinds. I don't get called by monsters but more like mediocre hands that are still putting me on a coinflip for my stack...
Some examples:

Party Poker
No Limit Holdem Tournament
Blinds: t200/t400
5 players
Converter

Stack sizes:
UTG: t1280
CO: t4790
Button: t1450
SB: t7580
Hero: t4900

Pre-flop: (5 players) Hero is BB with 8[img]/images/graemlins/spade.gif[/img] 8[img]/images/graemlins/heart.gif[/img]
3 folds, <font color="#cc0000">SB raises to t1000</font>, <font color="#cc0000">Hero raises all-in t4900</font>, SB calls t4100 <font color="aaaaaa">(pot was t5700)</font>.

Flop: 3[img]/images/graemlins/diamond.gif[/img] 4[img]/images/graemlins/diamond.gif[/img] 9[img]/images/graemlins/club.gif[/img] (t10600, 1 player + 1 all-in - Main pot: t10600)


Turn: 2[img]/images/graemlins/diamond.gif[/img] (t10600, 1 player + 1 all-in - Main pot: t10600)


River: 2[img]/images/graemlins/heart.gif[/img] (t10600, 1 player + 1 all-in - Main pot: t10600)


Results:
Final pot: t10600
<font color="#ffffff">SB balance 12480 bet 4900 collected 9800 net 4900 Qd Td </font>
<font color="#ffffff">Hero balance 0 lost 4900 8s 8h </font>

-or-

Party Poker
No Limit Holdem Tournament
Blinds: t200/t400
3 players
Converter

Stack sizes:
Button: t3440
Hero: t3710
BB: t12850

Pre-flop: (3 players) Hero is SB with 9[img]/images/graemlins/diamond.gif[/img] 8[img]/images/graemlins/diamond.gif[/img]
Button folds, <font color="#cc0000">Hero raises all-in t3710</font>, BB calls t3310 <font color="aaaaaa">(pot was t4110)</font>.

Flop: 6[img]/images/graemlins/diamond.gif[/img] A[img]/images/graemlins/heart.gif[/img] 3[img]/images/graemlins/heart.gif[/img] (t7820, 1 player + 1 all-in - Main pot: t7820)


Turn: A[img]/images/graemlins/spade.gif[/img] (t7820, 1 player + 1 all-in - Main pot: t7820)


River: Q[img]/images/graemlins/heart.gif[/img] (t7820, 1 player + 1 all-in - Main pot: t7820)


Results:
Final pot: t7820
<font color="#ffffff">Hero balance 0 lost 3710 9d 8d </font>
<font color="#ffffff">BB balance 16560 bet 3710 collected 7420 net 3710 7h Th </font>

Especially the second hand is questionable in my opinion. I know this may sound like some lame bad beat whine(I know these aren't bad beats) but I'm really just trying to learn how to play the late stages in a SNG(I come from playing cash games). Thanks for your replies.