If the 50mm f1.8 is your only lens, you're working in a slightly telephoto range with the 90D's crop sensor. The camera's field of view is a bit narrower than what you see with just your eyes. Adding something like the EF-S 10-18mm lens may open up a whole new way of looking at your subjects. Landscapes will look more naturally expansive. Shooting buildings or other objects up close will show a more dramatic perspective. And you won't have to back up as far to get your subject fully in the frame. Keep the "Rule Of Thirds" in mind to keep your shots from looking too, ummm, boring.
Also think about all the places you go where you wouldn't normally bring your camera. I'm talking about public places like parks, street fairs, farmers' markets, auctions, car shows, free outdoor concerts, carnivals, food trucks, yard sales, etc. Bring your camera next time. Shoot crafts, artists, foods, street scenes, colorful costumes or performers. Or if you're feeling especially brave, ask a friendly looking group of strangers if they would pose for a group photo. More often than not they'll usually co-operate, especially if you offer to email them a copy of the shots.
Come to think of it, I need to get out more and follow own recommendations.
