First of all u have to select the leaves which u are going to make according to that. Make sure that there is no dust in that. Just keep this in between any big book or newspaper and press or keep any weight thing over it. leave it for 1 week or so. meanwhile just change the side everyday so that the leaves should not get spoil.
After a week u can get the dried leaves, now remove this carefully from the paper or book. apply some varnish over it and place it on the paper as u want.