As increases, decreases can be made in the middle or end of the tissue.
The easiest way to decrease 1 stitch is to skip 1 basis stitch. To decrease 2 stitches skip 2 basis stitches.
Another way to reduce is to close 2 stitches together as if they were one. This can be done in all the basics of crochet. work 1 stitch on 1° stitch from the previous row, unclosed. Insert the needle into the next stitch and work another point unlocked. Close the two points together.
Another method is to let noncrocheted 1 stitch at the beginning or end of the row. In the beginning of the row weave Slip Stitch (insert the needle at a point of the previous row, attach thread and close) the amount of stitches that should decrease. At the end of the row, stop working the number of stitches to decrease and turn the tissue.