I am sure you have heard of GPWS (Ground proximity warning system) or the newer EGPWS (enhanced).
This system is very helpful. It yells at you when you get too close to the ground or terrain when you are not approaching a runway. The typical: "WHOOP, WHOOP, PULL UP
" or "CAUTION TERRAIN".
We have another system in our cockpit. A terrain display. It is colour coded and shows you the highest terrain around you. It is either green, yellow or red. Green: no problem, Yellow: use cation there is terrain nearby, red: DANGER. If it is red, then the terrain is close to you and more important at least 500' higher than your current altitude.
These 2 things are very helpful to avoid CFIT. our charts are good as well, they have colourcoded areas as well. They tell you how high the terrain is and on those charts you can see the minimum flight altitudes. Don't go below them and you should'nt have any problems. And with the nowadays accuracy of the navigational systems, you know exactly where you are.
I hope that helps you a bit.