Roses don't come from nothing. Rich soil produces more blooms. Compost - lots of organic matter added to the soil when planting will improve your soil and produce healthier roses. Water - at least one inch of rain a week. If it doesn't rain, install a soaker hose and let it run on low overnight once a week.
Consistent moisture keeps the roses healthy.
Color - Roses come in pinks, mauves, reds, whites and yellows, with variations on these. If you want to mix roses together, but you're not sure about the color, get some colored pencils and color on white paper the various colors you want together. Then, you'll see if you like how the pink looks next to the mauve or yellow. Fragrance - many newer roses don't have any fragrance. If fragrance is important to you, be sure to look for roses that can produce the fragrance you want.