Made some tarpaulins for my wagons but what can I use to look like real rope to tie them down with !

Cotton thread???

Kevlar /fly-fishing thread much thinner...

I've used cotton thread but it's quite 'fluffy'. I've soaked it in superglue to tame it, but have heard that a coating of PVA will also do the trick (and probably much less 'stickily' than superglue).