Do not pull near the end of the blade, the prop is at it's thinnest and you have the longest leverage.
It takes some practice but with a hand on either side closest to the spinner you can even steer a SE airplane as you push it back.
DO NOT push on the spinner, depending on make and model it can be fairly easy to bend the spinner back plate which can cause the spinner to (ever so slightly) wobble which will mean cracking over time.
In very extreme (rare) cases it can cause spinner separation in flight.