Whenever I take a SG reading with my hydrometer I have a hard time getting an accurate reading because of a few mm of foam at the surface. Does anyone have any suggestions on how to get rid of the foam?
You can try filling the tube up to (or at least close to) the top, so that when you lower the hydrometer, most of the foam spills over the edge. Once it's that high up, it's not too hard to blow most of the remaining foam off.
Don't forget though to give the hydro a dunk and spin to dislodge any bubbles stuck to the bottom of the hydrometer from an excessively carbonated sample.
I'm using a turkey baster to extract my wort/beer, I always slowly drain the beer out into the plastic hydrometer cylinder to decrease the amount of foam. I always like to give it time to sit and get to room temp, this should give it time to de-gas. I also like to take a test sample when it's warmer for a better idea of the flavor.