Praise, praise, praise, praise, PRAISE!
Every little thing she does right, the very minute she does it. Thank her for doing what she is told, praise her for playing quietly, for trying, for sitting at the table, for holding your hand, for giving that toy over etc etc.
It feels awkward, and you think, why should I? She should do that anyway, but I did a parenting course (incredible years based) and that was the single most useful thing I learned. They love praise, it motivates them, it also tells them clearly what they are doing right.
Otherwise, phrase commands in
a positive way. Easy when you get used to it. And be specific in your commands so not let's tidy up, but x, please put your bricks in the box.
Also keep no for when it has to be no, otherwise try and use "first we do x, then we do y", type response (if feasible)
Emm, what else, we already had a calm down corner which we still use but much less than before we did the course, now it is just for v aggressive behaviour, hitting, biting, screaming endlessly. If I am trying to stop a behaviour eg screaming I might say, talk quietly or you'll have to go to the hall to calm down.
Hth!