It just happened today I played another game I think it's good to see if I made mistakes, since I didn't won a single hand, but I didn't end up fourth nevertheless; some mistake in defense, not so sure if I made mistakes big enough to account for the lack of winning. Here it is:
http://tenhou.net/0/?log=2015091016gm-0 ... 00215&tw=0
Here some comments about things I noticed while playing or reviewing the game (E1/0 means East 1, 0 continuance, the number preceding the comments is the step); any comments also on other parts of the game are welcome; here the first game:
http://reachmahjong.com/en/forum/viewto ... 48&t=53424 Again, thanks in advance
E1/0
Step 5: I think it would have been better to discard

, but I don't think it's a serious mistake.
E2/0
8: maybe

10:

, I guess, since it's isolated.
Not sure if it was worth trying four triplets, or if it would have been better to stay in defence.
S1/0
I should have discarded East before.
S2/0
Not sure if ponning

was the right thing to do, I did so because Green Dragons pon, South pair and a dora, it's at least two han, maybe three if I draw/call South, which could give me a nice lead on third.
S2/1
5: maybe discard

, since

already makes a group with

, while

let me use
7: as 5, just with
In the end I went in defence, since I was 2 shanten and didn't want to risk dealing in and get closer to fourth.
S2/2
Not sure why I didn't discard dragons before.
In last step I discarded

also due to time, but maybe

would have been better? Pros, I would have been in tenpai (+1000 instead of -1500); cons, not sure how risky it is discarding

: it's safe for East and West, not sure for South.
S2/3
6:

, I guess, instead of
And then, defense.
S3/0
Bad, bad riichi: I didn't have a chance to gain positions, I lost the chance to defend, and I didn't even noticed two

were already discarded.
S4/0
I started with the idea of going in defense, I was even more sure about it when East kan'd

, I should have kept

(in fifth step).
In the end I was collecting safe tile; not sure if discarding

was too reckless, in retrospect I think I should have began discarding safe tiles sooner, since I had quite a lot of them against East.
S4/1
5: a bit risky discarding

, maybe, since West looked like a pin flush (not sure, though, since he already had a yaku could be something else, and being first also a quick winning was fine for him).