Hello.
I use the same method for all my PCBs made at home, and I want you to know that it works perfectly.
I print over magazine paper with a laser printer (but no SO glossy, otherwise it gets stuck in the printer...) quite thin, you can try with different ones.
Then I iron the PCB for 3-4 minutes and when I finish, immediately throw the printed PCB (with paper) to a water filled container. I wait 10 secs until it gets cooled down and then I remove the paper with a toothbrush.
Don't worry about the written magazine sheets, those are printed with ink, and it won't transfer to the PCB since it doesn't melt.
Make sure that you are really printing with TONER (sometimes another materials are used). Then, once you finished with the iron take an old toothbrush and remove the paper from the PCB. You don't have to do it so strongly because you may remove the toner. If you do it right and the toner keeps getting unstuck, try printing with another printer.
Then, don't leave the PCB etching for half an hour, if you heat the acid up you can get your PCB etched in 10 minutes or less. You can heat water and put a PLASTIC container with acid into it. Always check if it's already done, if you leave it by long times then acid will attack tracks and pads.
And as everyone says, clean the copper surface before you iron the PCB.