I press my seams to one side in opposing directions so they nest at the intersection. About the only time I press my seams open is to reduce bulk in some patterns.
When I am sewing strips of fabric or a number of rows together I also sew one seam in one direction and the next seam in the opposite direction. This really helps reduce the rows and fabric from stretching and the strip getting wonky. To help me keep track of the direction I put a pin in the end that I just finished. That tells me where I need to start sewing the next time. By doing this I can put my project down and do something else and still know where I am supposed to be. Hope this make sense.