Random Tip #3: Offer your seat. Also, help her with her seat.
In general, any woman or elderly person has priority when it comes to seating. When she walks into the room, stand, look around to make sure there is seating available, and offer yours if there is not. If there is seating available, but it is not as good as yours (less comfortable, poorer view of the events, etc.), offer yours.
If there is no more seating available, you may also attempt to acquire some more (extra chairs from another table, folding chairs from the closet, etc.).
The same goes even if you don’t have a seat. If you’ve been standing, sitting on the floor, or have just now entered the room along with the lady, you should still make sure that she has a seat before you even find one for yourself.