Starting new garden

Hi everyone!
I'm new in permaculture and this great forum too. I've got some knowledge from internet and read some books about permaculture. I just got an offer to build a garden on land unused for a couple years, maybe decade. One spot is situated in frontyard.It's covered with grass and it got around 25m^2 (269sq ft). Another is in a backyard and it's got around 64m^2 (688sq ft). It's covered with grass, various weeds, some dead trees and there are many rocks and roots in soil.

Other gardeners (conventional) in my country (Slovakia, Central Europe) have sown or they plant seedlings in this time. So my questions are: Which is the fastest way to prepare soil for seeds/seedlings in frontyard? Could I do sheet mulching or tilling and right after it plant/sow? There are another way suitable for this situation? And what about backyard? Do the same as in frontyard or sow clover, lucerne etc. And in fall do sheet mulch and start in spring 2014?
Thanks very much for your answers, opinions, ideas and suggestions

I'm new to permaculture gardening and don't live in your part of the world. With that caveat, I've made "lasagna" style gardening raised beds and started planting very soon after their initial construction by digging in a small hole in the still composting bedding, then adding a small "pocket" of compost and planting my seedling/seed in that. Pretty sure I've read about other people doing this for huglekulture beds also. Good luck!

Welcome to permies Jakub; and thanks for bringing this thread up Mary, good to have you here:)
The areas are quite large Jacub. Do you have plans to divide them with paths so you can reach the centre of each bed without standing on it?
As Mary says, there are ways to do things that allow for quick planting.
If you can wait, I'd plant a cover crop such as buckwheat/cereals/legumes and cut it in Autumn I suppose, leaving the roots in the soil and the tops on the surface.
How big are your rocks? If there's a few big ones, or lots of small ones I'd leave them, but if there's heaps, maybe a rock wall would look nice;)
I'm not into 'tilling' if it involves what we call a rotary-hoe or cultivator as it generally does a lot of damage, but if the soil's really compacted it's sometimes a good idea to loosten it up. A garden fork is pretty hard work, but effective: you don't want to turn the soil over, just loosten big chunks up.
Speaking of chunks, is your soil clayey? Sandy?
Sun?
I'd definitely leave any wood in the soil. Search 'hugelkultur'...

As far as the grass, I just put cardboard down, then fresh dug soil from trenches around the edges, seeds, then hey or mulch. I top it off with logs around the garden for a box like shape that keeps the water in and of course I included wood in the soil. My bean plants are getting big. There is an alvocado tree in there.Mix it up the permi way.

I am having a lot of success with ground level hugelkulture (as opposed to raised beds) on extremely sandy soil. I dug some trenches about a foot deep and buried old fire wood. Then cover with sandy soil a layer of newspaper to keep weeds down and a 3 "layer of compost. Finally I topped it with about 8" of straw mulch. Plant growth has been impressive.