"Weeds", unwanted plant growth, are things that will keep coming around no matter what you do so there is no real prevention that works. However there are steps yu can take that can minimize that problem.

Removing the soil that was there was not necessary and whatever you buy to replace it may have the seeds for many "weeds" in it. Fill the area back in, plant what you want there and then place the newspaper and cover it with some mulch to hold it in place. The newspaper allows you to use less mulch because it is an effective block for the sunlight new plants need to grow, but then a 6 inch thick layer of a mulch will do the same thing.

kimmq is kimmsr

One of the best things is to improve the soil to make weed pulling fast and easy. This will make weeding quick and less stressful. The more you pull, the less pulling you do later. It's always more in the first years but gets less as time goes by and the weed seeds in the soil get exhausted. Weed seeds live many years in the soil and exposing them to sun and moisture gets them going. Mulch helps keep new seeds blowing in from getting an easy start.

Remember the old adage. "One years seeding, seven years weeding." Get to it before the weeds flower and set seed and thereafter mulch regularly.

Everyone who has posted a reply so far is correct, as I am finding out for myself. I finally just bought one of those knee pads, started going out early in the morning when the dew is still out, and work on one bed at a time. My beds are looking alot better.