Enrich your soil to make it a hospitable environment for roses. Roses have high nutritional needs, so your soil needs to be rich, well-drained, and neither too acidic nor too alkaline. Invest in a soil test kit and use soil amendments, such as lime or sand, as needed. Incorporate generous amounts of compost, as well.
Evaluate the roses you already have. Identify which ones are doing the best, and which you enjoy the most. Consider at the qualities you're looking for in a rose, such as color, shape and size. Make a list of the types of bushes that are doing well, and why you think that is; cold-hardiness and disease resistance are often big factors in the success of plants. Heirloom varieties tend to be stronger than often-fragile hybrids. Look for new varieties that match the criteria for appearance that you've set out, and that also have the same durability factors that your existing top-performing roses have. You may also want to experiment with a few more delicate plants as you expand your rose garden and become more confident in your skills.
Go to your local garden center and check out online sources and catalogs to identify potential new additions to your rose garden. Write a list of good bets, which look like they will certainly do well in your garden, as well as more challenging plants. Purchase about 80 percent good bets, but don't forget to add some more interesting hybrids, even if they are a bit more challenging to grow.
Propagate existing roses that are already doing well in your garden. Propagation is an affordable way to provide your garden with new plants, and also ensures that you are working with plants that have already proven to work well in local growing conditions. You may also want to ask a neighbor, or fellow gardener in your area, if you can take cuttings from their roses, perhaps arranging a cutting swap.
Investigate pest and disease control methods, including co-planting other flowers. Organic methods are preferable to chemical methods, and there are numerous options for organic pest and disease control, such as organic sprays. You'll need to get a good handle on problems as your rose garden expands, since the addition of new, more delicate roses can make your garden more vulnerable.