Honestly, fitness/strength by itself will carry you further for 99% of the scenarios than any other type of prep/planning. Being able to do a full day of hiking in 4-6 hours and not be broken makes up for so many risks versus 6-10 hours because you arnt fit enough.
My gf did Hiddignh ravine with me on her 3rd hike, purely because she is strong and fit from Yoga.
The other thing is to pack less. It ties to fitness. You are extremely unlikely to starve to death. You probably dont need nailclippers, a second puffer, and canned tuna, apples ect. Minimize pack weight. Any over 13kgs for 5 days is overkill tbh. Less pack weight fatigue less risk of injury. Especially for females or males who are light.
Check the elevation and distance profiles for each day, and check that against what you usually hike. If you have only done max 13km and 800m gain with a 10kg pack and it was hard, you probably should avoid hikes that go to 16km+ and 1000m elevation gain, especially if its more days.
If you dont see someone for 10 minutes, stop and walk back to them.
If something looks too technical for you, look for a better alternative, if no alternative exists choose if you think the risk is worth it or rather back out and try again on another occasion.
If you made a mistake, then another mistake, stop and ask yourself if 1 more mistake will be too much risk. Dont progressively make more and more bad decisions.
Make sure you always have at least a good headlamp (Petzl, Black Diamond) and a way to recharge them on anything multiday. And a power supply for your phone, with a proper map app like Mapy.cz that works even with no signal.
Hydrate Hydrate Hydrate. Its unlikely youll overhydrate on a hike and is most likely the thing that will create risk beyond slip and falls.
I am also actually a believer of being as relaxed as possible. Stress is cumulative, mental and physical. Dont let 1 person do all the leading, swap out point duty every 1-2 hours. Everyone should be able to lead, read a gps map, make route decisions. And those in the back should also just check where splits happen. If you are ever even slightly unsure, take out phone and check the map.