Let start with the tools - this technique needs a very specific set of tools
As well as the usual super glue, pencil, ruler and the plasticard that you want to rivet you will need a pin vice with a very thin drill bit (the one i used here was 0.5mm) as well as some very fine tweezers.
On the right of the picture above you will notice a container. This holds the contents of a Brita Classic Water Filter Cartridge. Water filters are essentially made up of small plastic balls and small shards of charcoal. Simply get hold of a water filter and carefully cut the top off it (I used a small razor saw). Empty the contents in to a suitable container and you have a supply of rivets that should last a long time!
Here is a closer photo of the plastic balls that are inside the filter. It is these that we are interested in
Once you have collected your tools and have a suitable piece of plasticard to work with we can begin the rivetting work. First stage is to mark out the location of the rivets on the body work. Care must be taken at this stage as poorly aligned rivets looks both awful and unrealistic.
I find that for 28mm or 1/35 scale a spacing of about 5mm looks good. But you may find that others work for you.
After the positions have been marked out you can begin the drilling. The aim here is to make a small indentation where you want the rivet to be. You definately dont want to drill right through the plasticard! (Note in the picture below i would normally have a ruler placed so all the rivets are aligned, but i ran out of hands to hold it with! hence the wobbly rivet line!)
Once the holes are dilled, take the drill bit out of your pin vice and replace it with a short piece of fine wire. I use florist wire for this work. Put a blob of super glue on to a scrap piece of plasticard. Then dip the wire in to the glue and quickly transfer some glue to one of the holes you drilled.
Once the glue is in place grab your tweezers and pick up a plastic bead from the water filter. Place this in the super glue (the capillary action will draw the bead in) and then quickly wipe down your tweezers. If you dont wipe down your tweezers very quickly they will become a gluey mess! Here is what you will have at the end of this stage
Now simply repeat the whole process for all the holes that were drilled. Generally i try to work on groups of rivets in 10's, so gluing 10 in one go. Once you have got the hang of the basic process you can quickly speed up. I would also recommend choosing a whole load of size matched plastic beads before you start - the beads are many different sizes and some will fit the scale of your model better than others.
Here is a door i am working on at the moment for a diorama that shows lots of rivets in place pre painting
And here are some rivets in place and painted (in case anyone is wondering... its the inside to a chimera for a diorama based on krieg that i am doing. All parts were scratch build)