Nothing In Life Is Free
The cornerstone to teaching your new foster pup patience, politeness, and deference to you is... Sit.
First, of course, you need to teach her to Sit. This should take about a day.
Once she has that down, whenever your foster dog wants anything, ask her to Sit first. Before dinner: Sit. Before she gets to play with her new toys: Sit. When you come home from work and she wants attention: Sit. Nothing in your foster pup's life is free. She has to work for everything, and that work is: Sit.
As your foster pup gets used to the basic idea, raise the criteria. Ask him to move away from the object he wants (after you make it inaccessible by raising it out of reach or putting it inside a closed crate) and toward you, prompt for a Sit, and only then hand over the object. Be patient; it may take a while for the idea to click, but it's worthwhile. This exercise reinforces that impatience gets nothing, that all good things come from you, and that the surest way to get those good things is to do whatever you-the-trainer request.
While practicing the NILF protocol, you should also continue training the rest of the Obedience 101 curriculum and (if you choose) a couple of tricks. Prompt for those tricks once in a while, instead of asking for a Sit every time. It never hurts to get a little extra practice in, and it keeps your dog on her toes.
The cornerstone, however, should remain Sit. After a few days or weeks of this, depending on your foster dog's natural tendencies, she should offer Sit as a default behavior whenever she doesn't know what else to do. At that point you can relax it a little, although it doesn't hurt to keep it going and I would recommend at least continuing to request tricks and obedience behaviors before meals and other high-value events.
Here are two quick clips of my foster mutt Crookytail practicing the NILF protocol a little over a week after his arrival: Level 1 (Sit gets the marrow bone) and Level 2 (in order to get his dinner, which is locked inside his crate, Crookytail has to move away from the crate and toward me, Sit, and only then get his reward).
