Mise en Place

1. Turn your oven on to 350 degrees and plug in an iron turned to the hottest setting (cotton linen for the iron I am using). 
2. Set up an ironing board and ensure a solid surface for ironing the copper. In this example, I'm using a 2 by 4 on top of my ironing board to provide a hard surface for ironing the circuit board design onto the copper. 
3. Cut out the design you printed on the magazine paper to fit the copper board. Set aside the design.
4. Prepare a cold water bath in your sink or large bowl.
5. To enable easier transfer we will be heating up both the copper plate as well as the iron - this will ensure equal heat distribution for consistent ink transfer.
6. Cover a flat baking sheet with parchment paper, folding the sides of the parchment upwards to use as handles when removing the parchment and copper plate from the oven.
7. Place the copper sheet onto the parchment covered baking sheet, scuffed side facing up.
8. Once the oven is heated, place the baking sheet with copper clad into the oven for 2 minutes.

Setting the Design

After 2 minutes, remove pan from oven and use the parchment paper as handles to move the parchment and copper plate onto the hard surface for ironing.  Carefully place your design onto the hot copper plate, ink design facing down toward the copper.

Pressing the Design

Take the iron and gently place it flat down onto your design, pressing down hard for 20 seconds without moving the iron.  Pick the iron up and place it down on another part of the design - repeat this as necessary for the size of your design, taking care to make sure the edges are transferring. You do not want to use an "ironing motion" until you have firmly transferred all of the toner onto the copper.  Continue transfer for about 2 minutes.

Here I am using an ironing motion with one hand to ensure the edges are fully transferred.  I have an oven mitt on my other hand so I can hold the hot board while ironing.

Cooling Bath

Pickup parchment paper with copper and put the copper into the cold water bath, leave for 10 minutes.

Remove the Paper

After 10 minutes begin removing the magazine paper from the copper.  Use a wash cloth or dish sponge to remove any remaining magazine paper fragments.

Toner Transfer Complete

If the transfer is not satisfactory, do not continue! You need to start over by using Acetone to remove all the transfered ink, resand with fine grained paper, and repeat from the beginning. You will waste a copper clad if you proceed with an improper transfer.
Once your transfer is complete, review the board and look for any gaps or partial transfers.

Touch up the Traces

Use an ultra fine point Sharpie marker to fill in any gaps or missing traces. I retraced every line to ensure no gaps and filled in all vias (drill holes).
Make sure everything looks correct and that no ink bled over connecting any copper trails that should not be connected. The way your board looks now is the way it will look after the acid bath.