[Need help]D3DHook

if i inject d3d hook in running game it will crash. if i inject the dll at startup of the game its good 100% working. So what to do how to make it work for injection in running game? for alt tab its ok , working no crashes. (released the lines and etc)

Injection method?

other hooking method?
but who cares if you need to inject it when you are ingame
most games crash if you do it ingame

i have read something about dynamic hook