Im going to assume you are doing
40k tsons and their blue, and im here to tell you taht unfortunately. there is no easy way to paint them.
You have to make a choice, do you think piping in blue will be harder/faster? or trimming gold will be harder/faster?
Personally if you are rocking an airbrush i would go with painting the blue first then the trim.
Now the way I do it to get this result, mind you this picture sucks because it was before i knew how to actually take pictures.
How i do this is base the model in Cadgar blue from the can
Then layer the model with an airbrush in Saphire blue from reaper paint
Next i shoot a highlight of a ligher blue,
iirc i used sky blue mostly on the shoulders helmet and legs
Then shoot upward a shadow color, i used burgundy wine from reaper.
Now the magic trick part of this, get yourself some teseract Blue contrast paint form
GW, and then shoot that over then entire model, this creates a filter and helps blend the colors together and help saturates them, and REALLY can make it pop.
From that point, enjoy painting ungoldy amounts of trim.
Now something you can do to help is make sure you first paint all the gold areas in a brown, THEN paint them gold. Helps a lot.