Hi Mark
Just to chip in with my 2cents. I admire the aim, steady portolio increase along with increasing quaility images as you learn. I come from a macro background of editorial, but took the same approach to SS as you.
For me all my income comes from stock, macro and micro. With SS, I have been able to maintain a portfolia growth of 100 per week approved since November 09. It's a hard slog, and debatable wether more time should be spent on quality over quantity. As long as they are of a good standard I don't get hung up on this or RPI etc.
I'm up to nearly 3,000 approved, with the aim to double this by the end of the year (I won't keep up 100 per week every week!)
I started with photo's, and have increasingly moved to illustration, and the results are good. I only track the end figure every month, and it has steadily increased, with no signs of stopping. Up go 20 new images, some will be picked up straight away, but the whole portfolio gets a boost, and pics I had forgotten about are downloaded as well.
To give you an idea, excluding weekend's I have had double figures+ sales every day except 2 in March, with some EL's thrown in for good measure.
I realise this is not everyone's idea of a good selling technique, but results wise it currently works.
Quailty may win the day, but consistent mediocrity is more me.
Good luck with your next target
Oldhand