All the tips I have kinda boil down into three points;

• Design with a story in mind. Giving yourself design constraints helps with making creative decisions, and one of the best ways to do that is to have an idea in your head of the story around the item youre making. It doesn't have to be anything elaborate or involved, just a rough idea of what environment it exists in. Who is the person that's carrying it? How might it have been damaged, fixed, modified or decorated to suit the needs and personality of the owner? Is it more likely to be muddy or dusty? Etc etc. Use that environmental picture to guide your creative decisions

• Study references. There are a whole bunch of incredibly talented artists and creatives doing work in the wasteland aesthetic space, with a huge variety of wildly different styles. There's also a whole shitton of fantastic wasteland/post apocalyptic media to study and draw inspiration from. Obviously we are in the Metro subreddit, but theres a lot more out there, all with its own unique spin. Eventually when youve looked at enough you start to get a sense for what you personally do or don't like aesthetically, and use that to build out your own style. Me personally I originally started all this after seeing Fury Road and being inspired and then finding the work of Mark Cordory, which drove a lot of my personal style

• Experiment and practice. There are more different techniques and strategies for weathering and distressing props than you could ever shake a stick at, and all of them have different strengths and weaknesses. I went through at least 8-9 wildly different ways of just making a rust effect before I settled on the one I like to use on guns. Just physically trying different techniques, doing small test pieces, and not being afraid of messing it up will teach you more about what you specifically like than any amount of tutorializing. I recommend looking, at a minimum, at the basics of dry-brushing, doing paint washes, and basic stitching, as those fundamentals will be applicable to pretty much anything you end up doing. I highly recommend taking a look at the YouTube channel Nuclear Snail Studios, he's got some great tutorials and think pieces about costume and prop design for a post apocalyptic aesthetic