My typical Facebook ad budget split:
70% Prospecting (Cold Audience)
30% Remarketing (Warm/Hot Audiences)

Always exclude your remarketing from prospecting ad sets
Know your time lag to purchase to determine remarketing window
Leverage broad audiences / interest expansion

7 day click + 1 day view is my typical conversion optimization window
always optimize for purchase
automatic placements always except for story specific campaigns
CBOs with similar audience sizes
conversion (lowest cost bidding) or value optimized bidding

avoid audience overlap
no more than 15 active ad sets in account
leverage dynamic creatives with multiple copy tests
DPA for view content/add to cart
let your ad sets get out of learning phase before tinkering

There you have it. That’s how I run FB ads.