Weapon swaps, give some guys helms, remove helms from others, etc.
I'm on a piece of trash worthless iPad, so I can't embed the images, but here is a link to my gallery
http://www.dakkadakka.com/gallery/424943-.html?m=2
If you are looking for options:
Csm vehicles come with crew pieces that have chain Tabards. Helmets can be modified with spikes added or horns redirected.
Csm bulked up pauldrons are easy o make: glue on some extra plasticard (you can use the strip-layer method, cutting out strips at
th width of pauldron rims, gluing them on with plastic glue, and then filing smooth once set) and then attacking it with a file to roughen it up. And give it battle damage. Other options include chainblade bayonets. Sometimes, it's as little as making them bigger. The model could be plain, but padding the arm sockets, waist, shoulders and neck with 1mm of plasticard or gs... The model won't be much bigger, but he will stand apart from your regulars. Other thing I've done are ridiculous numbers of bionics, or saving up special helmets, either from the vehicle frames, or modifying champion helmets. Kit bashing with possessed frames are also an option: there's cool stuff in there, and depending on your warband, the "chosenness" May reflect differently.....