Two images showing the way I handle karat gold leaf. Top, the tip is held by the last two fingers of the right hand for cutting the leaf; bottom, the knife is now held by the last two fingers of the left hand. I work directly from the book of leaf. A book of leaf holds 25 leaves, between a tissue paper. I used to just insert a piece of mat board under the tissue, as a "cutting board" for cutting the leaf, but on a "bad day", this could be difficult with the mat board and the book all wanting to go in different directions. I've added a little touch that helps, though; double sided tape, framers ATG tape, holding the book to the mat board. I've used packaging tape as a surface on the mat board. The knife is one of the small, swiss army type knives, with a stainless steel blade; I've found they are the easiest to maintain a good edge on for cutting leaf. (The sign maker I worked with when first learning karat gold work, used the elongated fingernail, of his right hand, as a "knife". I did for a while, but kept breaking that nail.)
I'm patching "holidays, missed spots, holidays, get it" from the initial size gilding, so there is some cutting.
In the bottom image , on the back of my left hand, some small specks of gold adhering to the minuscule amount of Vaseline on the back of my left hand, rubbed in there to provide a place for me to pick up a little tack for the tip, so it can pick up the leaf. Cut the leaf to the size needed, brush the back of my left hand with the tip, (flat, long haired brush for handling leaf) to get some tack to it, pick up piece of leaf, and apply. In an earlier post, where I'm speckled, when gilding I'm usually "glittery", as I use the right front of my shirt to clean and dry the tip.
On size work, I usually work with the book, almost like "patent gold" when I can, rolling the leaf onto the surface directly from the book. No tip, no knife. Patent gold is a leaf slightly affixed to a sheet of paper that can be laid on the surface being gilt; useful for outdoor applications, as loose gold leaf is incredibly fragile.
Metal leaf, another post. And an aside, these are my techniques for an ancient craft, and they are not necessarily definitive.