Don't put rocks. They'll just get in the way of the roots (it's just not true that they help drainage... it's kind of an old wive's tale) Let the soil dry out (like wait a few days after the rain) and then loosen up the soil with a digging fork where you're going to put the bed. You could even double-dig it. Loose soil will help it drain a little better, and if it is a foot deep that will also help a ton. That organic matter on top of the soil will attract worms that will come and build tunnels. Sometimes standing water is just about having hard compacted soil that doesn't absorb water the way loose, friable soil does.

If you can place it on hiher ground, that would be great, but I bet you'll be fine.

Thank you for your response! yes, I forgot to mention that the soil on our backyard is very compacted, as in super-hard. I was going to till it a bit, but my husband did such a great job digging the hole, that I decided not to.

I can attest that material added on top will get the worms going!! I did this with my hard soil and it works. My beds are much softer and have good drainage.

I also add coffee grounds from starbucks a lot. The worms love it.

I ask the starbucks people if I can have their whole load of trash. They are happy to give it to me cause then they do not have to haul the bag to the dumpster. I get a huge garbage bag full. I spread it all over for the worms (not too thick or it can crust up and make a mess)

I see a lot more worms when I am working in my beds now.
Karen