I used to make boards like this all the time. Its often easier just to buy a pack of paper made for the transfer purpose (such as http://www.techniks.com/) since you know it will work.
If you use ferric chloride really take heed to the part about staining clothing, seems to always end up ruining some clothing so make sure to wear crappy stuff.
There is also a problem doing them the way he has done... if you use pads that are filled (as they are there) it can be difficult to drill the holes if using through-hole components. The drill bit will walk, or just bend because its so thin... using pads with holes in the middle makes it much easier. If you have a bigger board it becomes really annoying, especially if you have ICs with a lot of pins... they wont line up well.
When I read your comment, I thought, “Holy shit, he wants to use H₂O₂ because FeCl₃ is dangerous? Talk about ‘out of the frying pan, into the fire!’” but the Instructable you linked to just uses the standard 3% H₂O₂ USP solution, which isn't particularly dangerous.
I didn't make PCBs by myself anymore, but to me the messiest part was dealing with ferric chloride, so I expected this article to present some ways to avoid that material... Putting the mask on the copper surface was easier part (with that regards, the article presents a cool way to do it, though).
If you use ferric chloride really take heed to the part about staining clothing, seems to always end up ruining some clothing so make sure to wear crappy stuff.
There is also a problem doing them the way he has done... if you use pads that are filled (as they are there) it can be difficult to drill the holes if using through-hole components. The drill bit will walk, or just bend because its so thin... using pads with holes in the middle makes it much easier. If you have a bigger board it becomes really annoying, especially if you have ICs with a lot of pins... they wont line up well.