decorating a small dining hall....help!

[ncephas07]

so after some trouble with a loss of a venue, i came to terms with using the dining room the church has as our spot, and serving "refreshments" after and not a full meal.
the thing is, the dining hall is not big enough for everone to sit at once (even if we did cut the guest list lol)

they also have round tables and chairs there that we can use

my question is how should i set up the tables?
i know where the food table is going to go, and the cake table.
i orginally wanted a sweetheart table for us to sit, and if i can find a random small round table ill still have it n put it near the cake table so we will have somwhere to sit at.

my concern is about the other tables? how do i set them up and still make it look nice with just the small centerpiece and plain white table cloth?
i was orginally going to put colored napkins to add a splash of color, but since ppl will likely eat then get up, and someone else will sit there after, than thats out.

also the walls are yellow, my colors are pink and green, should i still add other decoration too?

any ideas or help will be greatly appreciated