If you want to do streaks like mine, it's pretty simple, but time consuming. If we zoom in on one of my models, you can see how I did it...
It was done as a two stage highlight, first painting the armour dark blue, then a medium blue...
Then a light blue...
You can do the same with dark red, medium red, then a brighter orangish red.
To do the streaks, it helps a LOT to have a good quality brush with a good tip. Start at the tip of the streak and create the point using the tip of the brush, then as you go down the streak press the brush more in to the model so that the streak becomes fatter near the base. I purposely didn't do my light blue streaks directly over the dark blue ones because it gives it a more random and rough look. One thing people often get wrong (when I've looked at other peoples' nids) is they do too many streaks and paint them too short/small, and then their lighter colour streaks aren't long enough. The light streaks as you can see on my Tyrant are still quite long, they're just narrower than the darker streaks. Gives the model a bit more depth.
But yes, very time consuming
I regret doing it because it takes me so long to do, even the small amount of armour on a hormagaunt takes me 30 minutes and the armour on something larger like a Ravener takes an hour or two.
That Tyrant you can tell was a rush job because half the streaks aren't straight, I was getting sick of painting them so went faster and became less neat. If you look at my Carnifex or Trygon they have much straighter and nicer looking streaks because I spent much more time on them than I did the Tyrant.
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2,000 points 
265 point detachment
Iron Hands: 1,850 