Don't tighten up -

[bennythedip2]

MCU poker tip: Don’t tighten up against loose foes. - By Mike Caro

One of the worst common pieces of poker advice is that if your opponents play loose, you should play tight. This makes no sense. What does it mean when your opponents are too liberal about the hands they select to enter pots?
Additional

It means most of the conservative hands you used to make money with are still profitable. But additionally, you can play many more hands you couldn’t have played profitably otherwise.

Although you shouldn’t play as loose as your opponents, you have more opportunity for profit, because they’re playing so poorly. So, relax your standards a little. Don’t play tighter. Play looser.

(There are some specific hands that might make money in a typical game that are less profitable or not profitable at all in a very loose game, but that’s beyond the scope of this tip, and it doesn’t change the fact that you should be willing to play more hands against loose opponents.)
Final truth

The final truth is that despite the age-old poker advice to play tight when opponents are loose and loose when opponents are tight, you can play looser in both cases. If they’re too tight, you take advantage by bluffing more often. And if they’re too loose, you relax your standards and play more hands profitably — just not as many as they do. — MC -