When new customers enter, assign them to tables that match the color of their clothes when seating them. You will build the color bonus by doing this, and will also help you find where a person is seated when things become hectic.
Combos
Do not wait for just one set of diners to be ready to give you their order or for them to signal for their checks when you have multiple tables. Instead, wait momentarily to collect multiple orders or checks at once to chain together a combo. This will result in more points and make it easier to keep up with all your customers. Double tap a table to pick up the bill and collect the dishes at the same time. However, if Flo's hands are full when gets to a party that wants its bill she will not pick up their dishes.
Dinero
Watch advertising videos to earn free dinero. Save your dinero to purchase restaurant upgrades, especially items that will reduce customer anger while they are waiting to be served.
Energy
Do not purchase energy segments unless you absolutely needed. As long as you do well in a level, you will be given enough energy to continue.
Keeping customers happy
Use coffee and other menu items that become available later in the game to keep the customers who are not ready to leave happy. Watch the hearts that are below each customer and get to them when you can, especially the ones that grow impatient faster such as Barb the businesswoman and Shakes the coffee addict.
Keeping Flo busy
Select additional areas for Flo to cover; the actions will queue up as she works. This allows you to make big chain bonuses that will eventually award a large amount of points at the end of the level. When it gets busy, switch your focus on surviving and chaining actions. Pay close attention to coordination and chaining tasks when thing are slow at the start of a shift. This will buy time to take you through busier periods when you have to make sure customers do not walk out. Do not seat a party of two at a table meant for four customers. If a party of four enters after that table is given away, it will start a chain of delays that will affect other customers. Purchase items that will keep customers patient while they have to wait in the lobby.