I would start by writing a letter to the staff explaining the changes you are trying to make and why. Be concise and to the point. State things in a positive way. Put yourself in their position. Would you like someone new coming to your job and changing things?
I do feel however, there are some things that are PTA related and some that are for the school to deal with. Starting a behavior program does not seem to be a PTA thing. If you want to help with a program the school has or is starting, that is a different matter.

Help, i am a new pto pres and things are heating up fast. most parents and teachers felt the pto was not effective (most of those didn't bother to help), so to try to be effective and successful, myself and new vice pres, dusted off the bylaws(which hadn't been used in years) and got to work, we met with the principal twice over the summer to have things up and running when school started. well, things started and the teachers are mad at the pto, apparently the principal never bothered to tell them about new programs he approved. one is a behavioral incentive program, which the pto is about just to cancel because we have soo many complaints from the teachers stating it takes too much time. i called the principal and he said no one complained to him. also the bylaws clearly state "all committee plans and spending needs approval from the exec board" in an attempt to organize the pto,we (the new officers) are sticking to the bylaws which also has teachers upset. the pto provides money for assemblies which a teacher is supposed to research then present to the exec board for approval..this teacher has booked 2 assemblies and contacted the treasure to pay for one already, told the treasures she had approval (NOT TRUE). anyhow i think my question is..should i try to by pass the principal and talk directly to the teachers ? we feel he is not passing information on to the teachers properly. we have tried desperately to get more teachers involved but they always act like we are only their bank acct and shouldn't have a say in how they spend our money. i have been told the teachers will only be involved with the pto if we change several programs..i think this is blackmail and will only let them dictate in the future anytime they don't like something. all the pto new programs are for the children and the teachers have complained about everyone. just to let you know that their were teachers involved in the planning process over the summer but they are mum now. what good is a pto without teachers? and what can a pto do without any support from inside the school?