Admiral:
Check out this tutorial on rivet-making. It’s a technique perfected by 40k scratchbuilders for tank duty in particular, and has become something of a little vogue in that niche these last ten or so years.
Abecedar:
very nice technique. I will try it and hopefully have more success than the pressed plastic ones
Skink:
Yes, i have seen that technique before. It looks good, although… It is extremely time consuming, only yields round rivets, and has the potential of making a veritable mess! You can invest a little extra ca$h and buy some FIMO or Sculpey, plus this. Putty rivets have the benefit of needing just a tiny drop of superglue to get an extremely resistant bond, although they are a little more fragile than glass beads. In addition, they come in an incredible variety of shapes: big, small, hexagonal, rounded. Check this video out to see the mold in action!
Admiral:
Good rivet tip, Skink! Share your rivet tricks here, folks. 
Nicodemus:
Nice tips, thanks!!
Several years ago I found a site selling thin rods that had a hexagonal cross section, perfect for cutting into bolt heads. It was pricey though and I can’t find the bookmark now… So only slightly more helpful than not posting at all 
Bloodbeard:
I’m a very big fan of the Greenstuff world mould. I have it in rubber, and when sculpting I put my excess putty in there. A very nice tool.
The next time I buy stuff from GSW, I’ll also get the silicone mould. I make make a ton of rivets with a quick pour of resin.
Nice tutorial though. I have a bag of those mini beads, for making rivets. But I’ve just planed to use them like this:
1. add a thin layers of greenstuff
2. put beads into that.
I very easy and quick for Bloodbowl shoulder pads etc.
Abecedar:
I’ve looked at the “mini” beads That I already have to see if I’d try it and at 1.5 - 2mm they are still big for model sized rivets. A land raider would need bigger bolts to hold it together of course.
Fuggit Khan:
I’ve always used resin bolts and rivets from this Ebay seller…easy to use, available in various sizes, and just drill a hole and insert the rivet in:
http://www.ebay.com/itm/Zinge-Industries-Medium-1-5mm-Hex-Bolt-Rivet-Sprue-x100-X2-Forest-Sprues-S-RIV04-/302262713687?hash=item466042fd57:g:nhYAAOSwn8FXR1a-
Grimstonefire:
The best way I’ve seen is to use the method they use on model aeroplanes. It’s basically extruding the rivet out by pressing plastic from the other side.
Something which I have tried in a very basic way, and it does work. You just need thin plasticard.
Very accurate and easy to do lots of rivets close together (as you see on the FW CD vehicles).
Jackswift:
These guys make a nice selection of plastic rivets in various shapes and sizes. Easy to use, just drill the hole and drop them in:
https://www.tichytraingroup.com
I have used their rivets very successfully for rivets and other fasteners when I want something more detailed like a hex nut with a bolt throught it.
I’ve have tried several other methods for rivets and most end up a bit ridiculous in the time and effort dept.
My favorite method is lazy simple. I drill small evenly spaced divots just a half a millimeter deep (sometimes 1mm) give or take essentially making small reverse rivet dots that look good to the eye painted add more than enough detail for your average model. Different bit sizes vary the look. Take care you do not drill all the way through the card. Works nice using .04 (1mm) or .06 (1.5mm) thickness card.