I find it easier to put sashing on each block before joining the blocks, but only one two sides. I cut my sashing strips on the lengthwise grain so there isn't as much "give". If you put the sashing on this way the sashing becomes part of each block and the points will match. I start out at the bottom left block on my quilt and work my way to the top right. The last row of blocks on the right side only gets sashing on the top of the block. The top row only get a short sashing strip on the right side. The top right block gets no sashing. Then I put a narrow border around the blocks.
I'd post a graphic, but I can't figure out how and the help section doesn't cover replies.