Regarding weeds growing in your annual flower beds, there are four ways to safely go about weed control without killing your flowers:
Pull them by hand. Pretty self explanatory. Just make sure you don't pull your flowers out while pulling out the weed!
Use a weed preventer at planting time. Your local nursery and garden center should have weed preventers listed for use in annual flower beds. Avoid weed preventer / fertilizer combination products as different types of plants might require different fertilization methods and types of fertilizer. Ask for a weed preventer only. Fertilize separately. If you can't find a weed preventer at your local nursery and garden center you can buy weed preventers to use in your flower beds and gardens online here.
Apply a 1- to 2-inch layer of shredded or chipped wood mulch to prevent weed growth. I prefer the shredded mulches because they usually stay in place better than the chips, which often wash away like little boats when it rains. Mulch not only prohibits weed growth, it also helps to retain moisture. Mulch is especially important in "raised beds" where soil tends to dry out more quickly.
Though I don't highly recommend it, you can VERY CAREFULLY spot spray weeds in your flowerbed with a broad spectrum, glyphosate-based weed killer, such as Killzall, whch kills just about any plant you pray it on. When your annual bedding plants have filled out it will be virtually impossible to use this method without damaging or killing your desirable plants. If you do use this method, make sure to spray when there is absolutely no wind and adjust the spray nozzle so that it sprays a stream rather than a mist or fog. And don't pump that sprayer up too much! Most local nursery and garden centers carry Killzall, Roundup, or other brands of glyphosate-based weed killers. I like Killzall and other brands because they're the identical product at often half the price of Roundup. If you can't find Killzall or another one of the less-expensive brands at your local nursery and garden center you can buy weed and grass killers for use in flower beds and gardens here online.