The Shulchan Aruch completes the entire section on the halachos of tzitzis (simanim 8-24!) with several minhagim involving our tzitzis during the recitation of Krias Shema:
1) Holding the four tzitziyos close to the heart during the entire Krias Shema. This practice is alluded to in the words: ‘v’hayu had’varim ha-eileh… al levavecha’ (…”let these words… be upon your heart”), because, as stated, the tzitzis remind us of the words of Torah. The Ariza”l instructed us to hold the tzitzis in the left hand; then, when reaching the third paragraph, to take them also in the right hand, and hold them out so that we may look at them. We should continue to hold them until we reach the word ‘la’ad’ (forever) in the bracha following the Shema, whereupon we kiss them and let them go from our grasp.
2) Looking at the tzitzis when making the bracha right before donning the talis.
3) Looking at the tzitzis when saying the words ‘ur’isem oso’ (you shall see it), then placing them upon the eyes and kissing them.
4) Kissing them also whenever we say the word tzitzis or Emes. Kissing a mitzvah object expresses our love for mitzvos!
When one looks at the front two tzitzis before him, he sees ten knots, which symbolize the Ten Sefiros (emanations) which are all interconnected, and sixteen strings. Together this adds up to the number twenty-six, which is the numerical equivalent of the four-letter ineffable Name of Hashem.
Finally, great is the punishment for one who does not wear tzitzis when he is obligated. Even greater is the reward for one who does wear them: he merits to see the Shechinah (Divine Presence)!