Cook, Serve, Delicious! 2!! (EP)

You lose a gold medal rating instantly if you deliver a bad or average order (every order must have yellow happy faces), also if any of the chores go un-satisfied.

In the event you do get, red or blue faces on an order. Try to figure out why it was like that because the game won't tell you, it's up to you to remember.
A common mistake is delivering an order before it's fully cooked.

The best advice I can give for this achievement is good rush hour management.
Make sure your prep stations are fully prepared when you get the rush hour alert.

You get 6 prep stations and I made sure I dedicated:
2 to french toast
1 to oatmeal (doesn't tend to run out as quick)
2 to griddled egg (lone item in yellow tab)
1 to boiled eggs (lone item in green tab) - it's important to keep this one topped up even though it isn't ordered because it gives you more waiting time which is key to beating the rush hours.

Also, try to stagger your prep because food does spoil once the pie chart timer expires. So for the french toast and griddled egg, make one of each at start then the second before the rush hour hits.

You'll get hit with 2 rush hours during this shift, one will hit about 11am and then another at around 6pm.

Ok, the key to the rush hour is, don't just instantly deliver the ready prepared meals like griddled eggs and french toast. Let them wait a bit then trigger them as late as possible because they will be instant and it doesn't matter if they are delivered before they disappear from the screen off the left side, it won't affect the rating you receive for the order.
The reason why I say leave them as long as possible is because if you do free up a slot during rush hour, they instantly get filled again. It's better to have a screen full of orders which are ready to go (like french toast and griddled eggs) rather than the dreaded pancake or even omelette orders!
You only have 8 slots for orders or chores to appear so just try to keep them occupied as much as possible with easier tasks (if you get what I mean).
Once you see the prompt that rush hour has ended then it is ok to free up as many slots as you like.
You need to find the right balance.

During rush hour, the omelette orders are PRIORITY, if you get hit with more than 4 of these in rush hour, you may be better off starting over. Don't be afraid to start over if you can't handle too many orders like that. Pancakes are ok, they only ever require 2 ingredients once cooked, it's easy to handle multiple orders of that if you're fast enough.
Another mistake to make is don't try to cook more than 3 things at once (unless you can handle that of course!), it is easier to manage up to 3 things being cooked and you can get this achievement by only ever doing that. As long as you don't leave the pancake and omelette orders too long, you shouldn't get into difficulty.
Oatmeal orders are easy to plough through as well. The best scenario you can have is a screen full with easier chores, oatmeal orders and french toast/griddled egg orders.

TheOnlyMatto says
I'll add that you shouldn't send food out until you've nearly lost it. The faster you serve, the faster they come because the rating gets higher. You shouldn't cook food until it is nearly lost. Same reason, buys more time. You can send orders, can't cook them tho, while you do the dishwasher. Just press X over the order (Hot station orders or meals already cooked).
Another tip now that I think about it. As long as you are prepping or cooking a meal it won't disappear. This is another great way to delay a customer without losing a perfect score.

If you are unlucky enough to get a wash dishes chore early on in rush hour, try and deal with this when you are able to. This is the only chore which can be problematic, it might be ok to leave a few of the others.

Another chore which I find tricky is the coffee one, it's easy to press the wrong button on these because it is actually an order but appears as a chore sized tile.

Also if you do happen to run out of prep items during rush hour, the best thing you can do is prep some more, otherwise the prep items turn into cooking orders (and they can expire and give you a bad order rating).

After rush hour, it's ok to leave a few orders sitting while you repair your prep area. Again just keep to the set up described above (2 french toast, 2 griddled eggs, 1 boiled eggs and 1 oatmeal).

If you make it through the second rush hour then you're pretty much done, just be careful not to mess up the last few orders of the day.

Sorry for the long guide, hope this helps :)