Thats a good tip about the glue looking like weld marks after these are painted. I would have never thought the googly eyes would add such a great effect either. I am definitely getting lots of great ideas here.
With weld marks if you paint them a lighter shade than the main colour and water the paint down to a degree it looks like welding. Those googly eyes are an idea I came across several months ago whilst doing a small craft job with my daughter. I've found that if you go into craft stores or where ever and take your time looking around (especially at stuff you normally wouldn't look at) you can get some ideas. You just have to look at things differently and imagine them painted up and glued to other things in your minds eyes.
I often take a look in discount stores, craft shops, hardware stores, chemists (yes that's right, I said Chemists), donation stores (charity places) and supermarkets (home wares/kitchen storage section). I've found over the years doing things like this and dioramas that if you think outside the box and look outside the box you can really come up with some novel ideas that you would never had thought of and you can find stuff that you would never of given a second thought too.
I have found that if you take your time, don't rush things and use a variety of options and never stay limited to what you're use too using you can come up with some really cool ideas.