You have to legally start a company. That means some legal work (you don't need a lawyer, but it helps). You need to do the books yourself - and because this is very different areas of tax law you really should hire an accountant (only an hour/month, but having extra eyes look at the books is useful). If you do this right you make more money, but there are problems if you miss some legal detail that W-2 employees don't have.

Many times you cannot get called as a 1099 as some places won't work with you. however most of the big consulting companies have others working for them on a 1099 and will be happy to deal with you. However the amount they pay you doesn't change so you have to really understand how to make tax law work for you to make it worth out. (perhaps you can give yourself a 401k with a match - check with the lawyers/accountants above to see if that is legal and if so what the rules are. If not there are other loopholes that work similar)