What tuutorial do you use ???
I guess #07 (Collision tutorial)...
In general search the API and/or the forum first (for all of your questions) !!!
for the camera height look at the
createCollisionResponseAnimator function in the API documentation and especially for the 5th parameter (ellipsoidTranslation)...
for the crosshair look here:
http://irrlicht.sourceforge.net/phpBB2/ ... php?t=4725
at the bottom of this thread is an example code...
you see, searching the docu and the forum probably solve most of your questions...