This isn't official, but it worked for me when I was playing. We tended to make the height of spells and effects smaller than their width, just because it worked better. We sometimes played on some old Warhammer, Mordheim and Necromunda scenery, and we found that this sort of stuff worked pretty well (with a range rule using inches for squares and a piece of grid paper that we'd put down anywhere on the battlefield for "instant" dungeon grids in outdoor environments. Lots of grid paper, we just had a book that we'd cut up to approximately the right shape to fit around terrain each time. Or just guestimate). Use "perspex" for a good see-through material to make range-cones out of.
Cone 2D: use a quarter circle. Make it out of see-through plastic. Have lines drawn on it for every 5 feet range (ie, each inch). Draw them with a compass. Then use the quarter cirlce.
Cone 3D: make another quarter circle. Cut it in half so that it's an 1/8th circle. Draw range lines on it. Then turn it on it's side and use it for "height" or depth of attacks to see if your normal 2d-cone hits something heigher or lower than you. Middle of cone is aimed at the initial target (so only 22.5 degress up/down of that is affected). If you're on a ledge, you can aim down (or whenever you want if you want to self-nuke). You can also aim up whenever you want. You can glue one to a quarter circle if you split it in half and glue it to the top and bottom on it's side, if you want a handy, all-in-one cone aiming tool.
Burst (area). While stuff is meant to be spherical, it's a good idea to fudge it not to be (ie:less height than width) if playing with destructable scenery. This is so you don't accidently nuke everyone or drop the ceiling on their heads. But yeah, just use a sphere because it's easy. Use a ruler to check range. Then make it smaller in the vertical axis. About 3/5ths for vertical/horizontal worked alright we found.
Flattening the area makes a lot more sense if you play in a 3D wargaming environment in 3.5DnD. It kind of simulates gravity. But mainly it's so that one cone spell can't wipe out and entire tower of archers in one cast. Areas/volumes get pretty huge in an outside (or huge inside) 3D environment