This was done with the hairspray technique, it was first model ever done with this technique and I think the hazard strips turned out great.
Obviously for this you need an airbrush, and considering you are asking for techniques with a brush I can assume you dont have one. My first tip would be get one if you can. In honesty I love airbrushing and with vehicles it really gives you so much scope to play with.
But in terms of using a brush:
Id say, you would want to paint the rust on the dozerblade first, get that looking nice and defined. Then
id use masking tape and tape the whole blade with strips of it, including both the black and yellow areas (so you have a fully taped blade).
id then pull off a strip at a time and paint on the yellow or black depending on what colour you want starting in the corner. while doing this make sure to leave areas where you want there to be rust, so what you could do is build up the coats with a stippling effect and then block in a little extra solid colour at the end.
Repeat that for each strip of tape (as the tape will help ensure you get clean edges. Other than that im not too sure the best way to get it to look like the rust is beneath.