To decrease the stitch count for the linked treble crochet stitch, you will need to stitch 2 of them together. See the photo tutorial below, or watch the video tutorial at the end of this article. For a tutorial on how to do the linked treble crochet stitch click here.
Linked treble crochet 2 together ( ltr2tog ):

1) Pull up loops in 1st & 2nd horizontal bars from the ltr stitch you just made and pull up loops in the next 2 stitches (5 loops on hook).

2) Yarn over and pull through 1st 3 loops on your hook, yarn over and pull through next 2 loops, yarn over and pull through last 2 loops. (ltr2tog made).
Linked Treble Crochet 2 Together ( ltr2tog ) Video Tutorial: