With the immersion method, I'm having trouble finishing the cards. Once I put them in the book and have changed the pages a few times I've left the card to dry, but I'm unsure as to how long to leave it because none of the cards that I've brought out so far have been perfect. Some have warped some have bent and others are just rubbish!
However, I think I've got my method up to that point down and I've found that to get a close to perfect card the "joining" procedure must be pretty thourough.
When you place the layers together it is important to ensure the borders match and that there are no bubbles under the surface. The last few cards I have made thouroughly have come out close to perfect.
I can also vouch for ironing the cards but again a procedure must be followed.
Firstly the cards must be as dry as possible. If there is any moisture still within the card it will try to evaporate and create air pockets in beneath the surface. Trust me I know

. Once the card has been ironed you have about five seconds to get it straight. I did this by quickly puting it between the pages of a heavy book and then appling pressure to the book. The card will cool down quickly and assume a more usable shape. I havn't got a perfect card from this method but I think it is possible if you use a harder surface to press the card between. The paper is too soft and will bend under pressure making the card bend with it.
I would suggest ironing your card only if it is dry and hence cannot be bent into a usable shape manually.