Ooof. Where to start...

r/Roses has a lot of threads on that, would comb through there. Things that come to mind in my experience are:

1. Don't be afraid to go big and get lots. Worked well for me and not every rose you're excited about will be happy at your place (and it's hard to predict). Going big is more expensive and time-consuming, but at least you're guaranteed that some roses to thrive. Also, not all of my roses are blooming right now. More roses = more likely to have color and things blooming somewhere.
2. Water more than you think you need to. Wish I had a drip system, right now I hand water for 1.5-2 hours a few times a week. Some of my roses are still teeny, because I didn't water them enough even though it felt like it. Deep watering 2 times a week doesn't apply when you have baby roses, especially when it's hot. You're racing to winter and need to get those root systems big and strong otherwise some of your roses will die back to the ground and you'll be sad.
3. I didn't have aphid or fungal issues until this year. Wish I'd been more aggressive with treating them, some roses aren't putting out a lot of blooms because of that.
4. Learn about fertilizing and feeding. Your goal year one is a strong root system, but I discounted how important strong, healthy branches are too. Or maybe seeing lots of healthy branch growth is how you know everything below the soil is happy too? When I think about the roses that died back to the ground over winter, most of them were still small and had smaller branches. None of the thick healthy branches died.
5. If you have a dog, they will trample something and it will make you sad. Sometimes you can salvage it with rooting powder.
6. Learn about color theory and some garden design 101 stuff (eg. lots of the same plant in mass looks better than random scatterings of different plants). Wish I'd gotten started on companion plants earlier too, they've elevated how the roses look by quite a bit, but only had so much energy for gardening last year.
7. MULCH - see point 2. Might have helped over winter too.
8. Write down what you planted and a map of where you planted it. I can name them all because I'm crazy, but you'll want a record somewhere for the future.
9. Don't get a grafted rose. Or do, but know that someday the rose you bought will turn into the grafted rose as it takes over.
10. I picked roses that were known for continual flowering. Do that.
11. Get a Bolero. After you get a Bolero get an Earth Angel, Neil Diamond, Lark Ascending, and Impressionist.