Im going for Dark Matter

So as the title says, im gonna do the grind. Ive never Done it before since i value my stats very high. Currently level 187 with a 3.19 KD.

I have done all ARs in Diamond and all SMGs in Diamond, ive got the XMG in gold and now on the PU 21 almost gold. I just really want tips from You guys.

Whats the best way and most effective in your experience?