My mom was a master rose grower and I learned 2 tips from her that I'll share. The first had to do with the "bud union", which is part of the plant where all nutrients develop for roses. It looks like a ball at the base of where the branches form. Any branch that comes out of the plant under the bud union will never bloom (a sucker), and you should always remove these as it takes away from the rest of the plant. The bud union can be next to the soil, but never under the soil. When you plant a rose outside, the height of the bud union above the ground is done in relation to how cold it is in your area. The warmer the climate, the higher the bud union over the ground. I'm not sure how high you would plant it in a pot (sorry). Protect the bud union at all costs by never letting it freeze (thus the height on outdoor planting) and if you leave the pots outside over winter, cover at least this portion of the plant.
The second: mom's best roses were ones that she grew in Arizona where the soil was pretty sandy. Her theory was that roses really didn't like over rich soil, and liked to dry out somewhat between waterings. You can drown a rose by over watering it.
Her favorite type of rose: Tea roses. My favorite type of rose: old fashioned or old world roses. Pick the kind you like best, but tea roses are more particular.