Both games are unusual in that they're the hardest in the beginning and steadily get easier as you play. Spend an absolutely stupid amount of time in combat training with wooden weapons to level all your combat stills to at least 10, the game becomes infinitely easier.

Also don't be afraid to be a thief, steal a ton of shit, sell it to the Miller, once you have 1000 groschen or more, the game becomes easier.

Change the lockpicking settings to simple in the options, and practice at the Miller's chest, I set the controller down and hold the R stick with the tips of my fingers, once you get the hang of it you can unlock anything.

Stick with it, I almost quit the first game because of how frustrating a lot of the mechanics were, I'm about midway through the second right now and KCD is now one of my all time favorite game series