I always sight the edge first, and take off anything like a crooked end, or belly, first. If only 2 feet of a 10 foot board has an end that needs dealing with first. I swing the guard aside enough to drop the board in a little ways before it touches the cutters, and run that end. Sight and repeat until you get something straight enough to start with, to work with.
Regardless of how crooked the board is, it might not make a complete pass until the last one or two.
I always sight every piece before it touches the infeed table, and plan a strategy how it will be dealt with. That may sound like it takes time, but I don't have to look at it long. Without a strategy, it will take longer, and you might end up wasting more of the board than you need to.
This tip targets those folks who post about poor results when jointing longer stock.
We all understand that a jointer uses the freshly cut material as a reference surface against the outfeed table. When jointing particularly irregular stock that is longer than your jointer, the freshly milled reference surface may extend past the outfeed table with still uncut material trailing behind.
Many of us deal with this by first knocking down particularly high spots with a hand plane but, some do not. I had occasion today to mill a long piece of stock and thought it was a good time to share a couple of pics. I use roller stands or other forms of support equal to the height of the infeed and outfeed, respectively, of the jointer.
This provides a consistent plane of motion that lets you only remove the stock required to get to a long, flat surface. I'm sure a lot of you have a lot of methods to handle this situation so feel free to share them here as well. there's always more than one way to skin the cat.