Whether pouring from a tap or a bottle, always leave a two-finger head on a beer. Plus, it looks good and helps maintain liquor costs. If a draft beer is pouring foamy, pour half of it, go do something else, and by the time you return the beer will have settled. Otherwise, you're pouring profits literally down the drain. There's no need to keep moving the glass up and down while pouring draft beer.
Beer only comes out of the tap so fast.
Sedimented Belgian and German beers should be poured slowly, the whole bottle at once. Remember not to pour the sediment into the glass when serving Belgian beers. There's no substitute for a well-informed staff. Many customers would rather ask a server than read a menu. And just as you'd expect servers to know what food they serve, they should also know what beer they serve.