I didn't really know where I was headed when I started this quilt 7 years ago. I just wanted to play with strings for a while and use up some of the strange strips that are always leftover when squaring up fabric during rotary cutting. A string is any odd piece of fabric that is long and skinny. I usually save anything that is narrower than 1.5 or 2 inches. If it is wider than that, I cut it into strips or squares.
I like to use telephone book pages for my string blocks. Any kind of paper works fine, but the thinner paper is easier to remove later. Start with a strip of solid black fabric for the center. I like to secure it temporarily either with a small dab of glue stick or with a pin. Glue stick is one of my secret weapons for paper piecing. It doesn't take much, but it helps keep everything where you put it.
Now just dig through the scrap bin and find a strip of fabric long enough to go past the edge of the paper. On the left side, sew a string of color and repeat of the other side with a neutral. Sew with a nice straight quarter inch seam through both the fabric and the paper. The paper will come out at the end, but it will let you know how long to cut your strings and help serve as the pattern. Even with strings, it is still important to have nice seam allowances and straight seams, they don't have to run parallel to one another, but they should not be curved.
Press the strings open on either side and you are ready to repeat the procedure. It is OK if one of the edges is not perfectly straight. You should still sew a straight seam, but you can use the top string as your guide. Then you can trim the stray edge of just let it lie.
For the corners, either try to use a wider strip, or find a triangle. I like to use the extra triangles leftover from joining strips of binding. If you have too many narrow strings in the corner region, it gets very bulky when joining the blocks together
When you have covered all of the paper with strings, trim the block to 4.5 inches. This is the most satisfying part of the process for me. Like cutting the crusts off of sandwiches, it leave everything looking so neat and tidy!Then just turn the block over and rip the paper away from the back. This is a messy job, but lightens of up the block and makes them easier to join.
Finally, sew the blocks together in groups of 4. The dark strings all point to the center of the block, leaving the neutrals to frame the corners.
I have not decided on borders for my quilt yet, but if you are not adding a border, make sure to stay stitch the outside edges. There are bias angles everywhere and SO many seams which would like to pop open during quilting. I think that I might add a nice wide black border to mine and then finish it with rainbow binding.