Hello there! Here is a very basic checklist
(1) You need a high school diploma.
(2) You need a bachelor's degree in whatever field you would like.
(3) You need to take the LSAT (Law School Acceptance Test) and achieve a satisfactory score. Anything at or above a 145 would be good.
(4) Once enrolled in law school, if you take a traditional schedule. You'll need to study for 3 years (full time) and apply to take the bar exam
(5) Upon passing the bar exam, you'll have earned your law license and can practice.
This is a VERY basic checklist, and there are other steps on the way, but these are the big five things.
Salaries - it widely varies depending on what type of law you want to be in. The highest salaries tend to be corporate law and tax law. You can make a killing in either of these professions. At the lower end of the scale are public defenders, and non-profit law.
It also depends widely on your experience and where you live, and where you went to school. If you have a degree from Yale and you're going to work in a prestigious law firm in New York, it wouldn't be unrealistic to expect to make $150,000 a year or more within your first year. On the other hand, if you went to work for Legal Aid I doubt you would make more than $50,000 per year (if even that much).
There are also advanced law degrees that can increase your earning power (such as a Master of Laws in Patents or Taxation).
Hours and commitment - this is a profession of sweat of hard work. The commitment will be enormous. The American Bar Association recommends that for every credit hour of classes that you take, you need to set aside 3 study hours per week. So if you take 4 classes @ 3 credit hours per semester, you need to put aside 36 hours per week to study - that's a full time job!
Its a huge decision. Make it wisely!