There are as many "successful" submission plans out there as there are diets.
You've got the 1-submission per day plan.
Then there's the 1-day-per-week plan, where six days are spent writing and one spent researching and mailing out submissions.
For those who really hate marketing, there's the 2-months-per-year plan, where 5 months straight are spent writing, and then the 6th month is used to research markets and submit everything.
And then for something really different, there's the $100-per day plan, where $100 in potential sales are mailed out each day (my current favorite).
Whatever the plan, it seems all of them follow the same rules as the multitude of diets out there: find one that fits you and faithfully stick with it, and you're bound to see results. The key is to stick with it, even when you haven't lost an ounce. Er, gotten an acceptance.