I'm always scared because I hate scratching my bikes.
If I'm just play riding/practicing (which is all I ever do anymore) sometimes there will be an easier part to ride first like a lower height/smoother launch/more grip. Often there's no other option so I might ride up to it a couple of times to see how it looks on the bike. If you can't ride the section first then visualising helps; feels, noise, real-time, as accurately as possible.
After that there's nothing left but to go for it. If I crash I'll get up and do it again if I'm able to. If I'm not hurt and my bike is rideable I'll know it wasn't so bad and convince myself I was close. Can't let it put the fear into me for later.