What is an artistic technique that creates a three-dimensional appearance?

Depends on the medium but if painting, this technique is known as Impasto, layering paint thickly on the canvas making the strokes of the brush or knife visible. When dried the paint appears to be coming out of the canvas creating a three dimensional effect and providing texture. one notable artist that used impasto for its more expressive qualities is Vincent van gogh.

Start with a good stem and on the top put a kinda wiggly line into a circle connecting to the stem then draw some squiggly lines in the circle that should be about 3-2 inches long