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chaining is actually the easier way to beat levels if you can, plus it is generally the only way to get expert, it's impossible without it. 
 
For instance, when the restaurant opens you generally start with only one or two groups of customers, depending on the level. 
 
I like to seat as many as possible, get drinks, then wait for all the menus to go down and then hit two tables in the beginning, take them to the counter get two more, and so on until I have picked up all the orders.  Then I give drinks again to boost hearts.
 
After drinks to one customer, I start handing out all the food to all the customers, then another round of drinks, then I give out all the desserts, drinks, give out all the checks, then lastly pick up all the dishes.  usually flo can only carry two things at a time so obviously this has to be done in pairs.  For instance, four tables would go like this
 
table one-order, table two order.  Take to counter
table three order, table four order, take to counter
drinks to table 1
table 1 food, table 2 food table 3 food table 4 food
drinks to table 2
checks can be handed out all at once but make sure you only click a table once because if you double click you will give the check and then pick up the dishes.
Once all of the checks are handed out pick up the dishes and seat the next group.
 
Sometimes a customer will ask for something that will break a chain, that's okay, just try and stay on top of chaining as much as possible.  If you get stuck the forums are a great way to get a seating plan and walkthrough for a specific level.
 
I hope this helps.