Did anybody get a really high SAT score by studying alone?

i studied alone and got a 2100 the first time and then a 1800 the second time. i really want to get into a good college so i am aiming for a 2300. did anybody do it by studying alone? what did you do? my weak point is essay writing and math. what was your weekly schedule and how long did you spend on that? all my friends are going to academy/prep schools but i can't afford it.