Any tips on achieving a scale looking bent fender?

Get some lead foil. Form it over the kit fender. Bend the hell out of it.

You can copy the fender with lead foil, like Robert mentioned, or hollow out from underneath using a Dremel (cover with mud afterwards), and bend.

Not a fan of lead foil... usually too soft. I recommend sheet brass or copper. You can torch it to to make it less rigid.

You can also go old school. Thin out the underside of the plastic kit part. Then carefully heat and reshape the part.
This is much more technique sensitive and you only get one attempt.

The nice thing about using foil is that once painted, you can poke holes in it. Of course, sheet metal on tanks rusts while foil on models doesn't. But that's why we have rust-colored paint!

Lead foil is soft, but then, I touch my models as little as possible after they're finished. Heavy duty foil is an option as well - the kind found in a one time turkey basting pan. But I like lead foil because you can emboss details like treadplate by rubbing on it with a stylus. For plain flat surfaces I've used brass shim stock, but it's rare that you can use it without some sort of modification - bending an edge on it using your PE bending tool for instance.

And you can stiffen up lead foil and you're done working it with a coat of CA on the underside. I suppose plain old Elmer's would work too, but I haven't tried that.

Sorry for my ignorance, but this lead foil: are you replacing the plastic fender with the metal one?

How would you be able to bend it on top of the plastic?

Yes, replacing the original. It's very pliable, so with patience you can even get it to replicate a rounded fender like on a car. People will tell you they use lead foil from wine bottles, but if the are they're drinking some very old wine. It's almost never used these days. I've got some I can send you.

I might be interested in that.

I guess you would shape it by bending it around the plastic fender then?

I have used aluminum foil, a heavy duty version and it worked well.

Aluminum foil (cookie sheet, pie plate) doesn't work well with compound curves - it will just crumple and kink. Lead foil is much more malleable and modeler-friendly. But I still like thinning the plastic part from the inside with a Dremel and damaging the part accordingly.

Copper and pewter sheet are also options. Forming over the kit parts can work in some instances but it depends on the kit parts. If they have other details moulded in place, you might be better to form them over a blank made from styrene or similar and then adding the details later. For example, a lot of German trackguards are made from a metal frame with sections of pressed treadplate attached to them, which is hard to replicate convincingly other than by copying the original construction method.

it depends on what you want to do, if you want to damage only a small part, such as the front, replace only that, if you want to damage everything instead you replace it all, but maybe in that case it is better with a PE fender with all the details