Above all, do not push the police or try to swat their hands away. That would be assaulting an officer and any slight injury to them will turn your minor misdemeanor arrest into a felony. A petty shoplifter can wind up going to state prison that way. Obviously, striking an officer can result in serious injury to you as well. Try to resist the temptation to mouth off at the police, even if you have been wrongly arrested.
Police have a lot of discretion in what charges are brought.
They can change a misdemeanor to a felony, add charges, or even take the trouble to talk directly to the prosecutor and urge him to go hard on you. On the other hand, I have seen a client who was friendly to the police and talked sports and such on the way to the station. They gave him a break. Notice he did not talk about his case, however. Do not believe what the police tell you in order to get you to talk.