Leaving comments in the gallery is best way to get your count up. No time limits between posts. Join something like the Very Laid Back Challenge or some other ones that gets alot of images posted to it.
Also joining a really chatty thread helps to up your count, too.
haha...i am going to see if i can make it to the next level by the end of 2008 which means I have to post like 400 times between now and december...we'll see how that goes and if I am able to complete my 50 layouts by the end of the year, and I am only on number 7