Dosa batter needs to ferment properly for them turn turn out light and fluffy. If the weather is very hot, ferment for 6-7 hours only or if it is cold, ferment at room temperature for atleast 12-14 hours
Salt can be added just before making dosas if the weather is very humid and hot, this prevents dosa batter from turning sour
Adding poha/avalakki makes dosas extra light. I add it to most dosa batters
Methi seeds allows quick fermentation of dosa batter and also imparts a nice golden colour to dosas
Dosa batter should not be very thin, thick enough to be pourable and spreadable. Spread only lightly