Part three in my occasional series about how to plant a garden.
Previous entries (about sun you get and climate) are here. You have now figured out where you want to plant your garden bed. Take a hose and use it to outline the bed. Then take a can of spray paint (the kind used to mark goal lines and such) and spray along the hose. That's the planting area.
I can't emphasize the next step enough. Get a can of Round-up and spray everything inside the lines. Round-up is a non-selective herbicide and will kill everything. If you don't do this, you will battling weeds for the rest of your existence. It's no fun and you will likely lose.
Just a note, Round-up works by direct contact with leaves and stems. As soon as it hits the soil it breaks down and is harmless. Therefore, I don't consider it dangerous to the environment. I don't use any chemicals except this one. After you spray, wait a week and clear the dead vegetation. Spray anything that's still not dead. Some weeds are very persistent and may take a few applications.
A philosophical note. What is a weed? A weed is any plant growing where you don't want it to. For example, if you like dandelion tea and like to eat he leaves, you might consider a dandelion patch a good thing. I, otoh, do not. Or, in a different direction, I like to grow hollyhocks. It's a big plant (4 feet tall in six weeks) with huge leaves. It seeds pretty prolifically, so this year I had several hollyhock seedlings. I yanked them all because if I had let them grow they would have crowded out my other plants. So, in this case it was a weed.