One of the thing I'm struggling with at the moment is when to wait for a better wait instead of going for riichi/winning; I had this hand:
with

in the ponds; I could drop

and go for winning, waiting for

; or I could drop

or

and wait, since with

(11 tiles) I have a better wait and pinfu; I discarded

, then I drew

, so:
I could discard

, but I'm in furiten, so again I discarded (I think)

; I drew

, so:
I'm in tenpai again, waiting on

: same as the initial kanchan, so I discarded

and waited; next draw was

, and I declared tsumo.
Does this make sense?
Edit: I first went tenpai (waiting for

) on the sixth discard.

weren't in my pond, they were in my opponents'.
I don't think my opponents looked dangerous: no one had meld showing something flushy, neither their ponds looked that way, or for some outside hands; it was early in the game (it was I think around East 4) and in the hand (sixth discard); I was second with around 3k on the third and 8k on the fourth.