Rose people seem to favor laying down some kind of organic mulch (meaning not necessarily organic-certified but simply some kind of shredded organic materials rather than plastic/mineral weed barrier) for weed control.
Sez here mulch should be applied in early spring but you can mulch any time during the growing season if you remove the weeds and lightly rake over the soil. Spread the mulch 2-4 inches thick and leave a little space around the base of the rose.
Mulching is probably the best investment in terms of maximum payoff in improved appearance for minimum time and effort. Fertilizing once a year or so probably comes next. AFAIK just get any decent commercial rose food or fertilizer and follow the package instructions.
If the bushes look good and don’t have pests, then I wouldn’t bother experimenting with watering or pruning or shaping. If it ain’t broke don’t fix it, and changing a plant’s water intake or making cuts on its branches can sometimes make it less resistant to diseases or pests.
Likewise, make sure you get good mulch from a decent supplier that won’t be harboring pest larvae or other undesirables. The last thing your roses need on their territory is a 50-pound sack of Trojan horse concealing critters that want to kill them.