I must say.. I use to be an open seam presser.. but I bought a book from Eleanor Burns and she presses her very specific for how she needs the blocks to line up. So if you are following a pattern do as pattern says.. otherwise just to be the same all threw the quilt.. so you don't have some one way and some others.. your back should look as nice as your front.. trim and clip where necessary.. neatness is the most important and press as you go.. I love the apposing seams they make the points and the seams line up perfect every time with out much work.. they melt into each other.