Just Do It. Don't just put the rose in the center of the frame, look at the overall composition inside of the viewfinder. Look at the edges of the frame. Quit shooting everything horizontally already. Half of the world is horizontal and half is vertical.
Wind is Bad.
Wind is the enemy. Shoot in the morning, because there is usually less wind at this time. Professional films are lower contrast and have a wider color range. Sure they cost a bit more, but the results are worth it. There is a reason that transparency film is the standard of the professional world.