Use a reference photo if you can't draw a rose from memory. Start with you 0.2mm needle and black paint. Hold your airbrush three to five inches from the canvas and draw the outer edge of your rose, including the stem and thorns. Add a couple of lines inside the rose outline for folds in the petal.
Switch to a 0.4mm nozzle and apply red paint to the inside of the rose. Hold the gun three to five inches from the canvas as you apply the color in long, even strokes. As the rose begins to fill in, go over some of the edges of the lines for the petals to deepen the color. This gives shade and depth as well as creating a more vibrant color effect to your rose.
Use your 0.2mm needle to fill in the stem with green paint. Apply the color lighter in the center of the stem and darker around the edges, blending with the black outlines to create the illusion of thickness.
Go back over the rose using your 0.2mm needle and apply light layers of black around the petals of your flower to further deepen the shading and to give your rose an almost 3D effect. Add a few intermittent black lines to the stem to give it a final textured appearance.