[Closed] Go to the back of the class.

Have come to the conclusion it's me, not the bike, and formally request forum help!
I know enough on bike maintenance to fettle and tweak, and becomming braver over the last 12 months or so have changed forks/ on one and headset bearings on both my bikes ( both giant)
They both now give out an intermittent creak when I'm out playing from somewhere in the headset/fork region. I have to accept that I am the single point of failure, is there anyone with the knowledge of what I have done wrong and how I make it better?
Tvm
M