As requested, here is a step by step approach to level 6 in the museum:
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Take the stone tables as they're lighter and easier to see! Go to the podium first until the hearts release before putting out flowers. Go back to the podium and let the hearts release again. By this time you should have everyone for the first round.
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Tables are numbered from left to right, 1 - 3 being the row nearer to the counter. Put the blue and brown girls at table 6 and the green and blue on 4. Put the family on table 2 - you will need a highchair - and the 2 sets of yappers on tables 1 and 4. Put the stars on the bench. Take the orders and give out the food, then return to the podium. Do desserts and if necessary, return to the podium between cashing up and clearing. Put out new flowers.
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Put the hungry men on the completely brown table (either 1 or 4 depending on how you placed the yappers) and let them order and get their food before starting to place the rest. Then put the 4 grannies at table 6, the blue critic at table 3, the stars at table 2 and the alternately blue and brown girls next to the hungry men.
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On the next round, put the brown bookworms at the completely brown table, the brown critic in a brown seat at the table next to them and the 2 blue, 2 brown girls at table 6.
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Final round, put the remaining girls at table 1 or 4, the teen girls at table 2, the teen boys at 3 and the yappers at 6.
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This should get an expert score.

You said: "Tables are numbered from left to right, 1 - 3 being the row nearer to the counter. Put the blue and brown girls at table 6 and the green and blue on 4. Put the family on table 2 - you will need a highchair - and the 2 sets of yappers on tables 1 and 4..."

This puts the green and blue girls at table 4 at the same time I'm supposed to seat yappers at table 4, doesn't it?

Btw, I see the "brown" characters/seats as red.

Thanks,
nealsmama

They're brown on my screen.

Sorry, the yappers are on tables 1 and 4 and the girls on 3 and 6 with the family on 2 and table 5 empty. Hope that helps.

Yipieeeee...

I did it- finally.

Thanks a lot for your help, lizzie !

Sille

well done, silke! lots more fun ahead with the rest of the levels!!