I don't know what you mean-
on prehardened blades, ie those you buy prefinished (from Jantz, knifekits...whatever) ...the holes are drilled, the curves are there...there is nothing you can do
Give us a better question, but first...
Read these books, watch these videos:
This one has a nice list
http://www.knifedogs.com/showthread.php?t=5285
This thread on BF has links to some of those books linked as online, or pdf previews.
http://www.bladeforums.com/forums/showthread.php?t=603203
A good HT basics video
http://www.archive.org/download/gov.ntis.ava08799vnb1/ava08799vnb1_512kb.mp4
Green Pete's video on how to make a Mora style bushcraft knife - simple jig stock removal with hand tools and a neo tribal / unplugged type heat treat. "Green Pete" posted it for for free distribution.
It is available here for those who can use torrent files. + plus much more too.
http://thepiratebay.org/torrent/4995247/Greenpete_s__Knifemaking_Basics_-_Make_a_Mora_Bushcraft_Knife
Comments on the books
The $50 knife shop is popular and starts a lot of people off but:
I find it confused me for a long time.
The goop quench is BS, there are commercially made quench oils available, (maybe even mentioned in the new edition)
Found steels are interesting,but require the skills of an experienced smith to be able to work and heat treat properly., you can buy proper steel cheaply(mentioned in the new edition)
Cable damascus is interesting, but not a beginners project either.
It leads you to believe that forging is necessary, but you can just file and grind everything away to create a knife (stock removal)
I like:
David Boye-Step by Step Knifemaking
Tim McCreight-Custom Knifemaking: 10 Projects from a Master Craftsman
Forging:
Lorelei Sims-The Backyard Blacksmith - I agree that is a good one , forging in general no knifemaking.
Jim Hrisoulas- has 3 books on forging, all 3 are good &available on Amazon
There are many videos available now, some are better than others, but all better than nothing.