Burying the Foreskin
While the Jews were in the desert they circumcised their children and the dust of the earth would cover their blood and foreskin.  Later on when Bilaam was called upon to curse the Jewish people he replied, “Who can count the dust of Jacob?” (Numbers 23:10).  This statement was referring to the Foreskin that had turned into dust.  Hence, this is a source for the custom of burying the foreskin.  Another origin for the custom is associated with our forefather, Abrahams, great humility to G‑d.  He said, “I am merely earth and ashes” (Genesis 18:27).  Therefore, placing the foreskin into the earth alludes to his great humility.

Spices (Bsamim)
Some Sephardim have the custom to smell spices after the blessing over the wine.  The custom is based on a midrash.  It relates that after Abraham had circumcised his entire household, he made a pile of all the foreskins. The fragrance of the foreskins went up to the heavens and G‑d considered it like the fragrance of incense being burned.

Sholom Zochor 
A meal is held in honor of the newborn on his first Friday night in this world.  One of the reasons for this custom is based on the midrash that recounts a parable between a king and his visitors. The king makes a decree that in order to have an audience with the king one must first pay respect to his noble queen.  The queen represents the Shabbat and the kings’ audience represents the Bris Milah.  In order to have the child connect with G‑d through the Bris Milah one needs to pass the Shabbat; the meeting with the Shabbat queen. 
Another reason given is based on the tradition that while the child was in the mothers womb an angel was teaching him the entire Torah.  Before he was born the angel gave a tap under his nose and made him forget all of it.  Therefore, we come to console the child and his family on the loss of his Torah knowledge.  It is for this reason, that at the Sholom Zochor we serve chick peas, a mourner’s food.

Leil Shimurim (Night Watch)
The night before the Childs bris a night watch is held in the house of the newborn.  Since the reward for the mitzvah of milah is so great, there is great opposition to its fulfillment by the Satan.  Therefore, it is a custom that men of the family stay up and learn certain parts of the Torah to ward off these spirits.  It is also a custom to have a group of children come and recite the ‘Shema’ and other verses of protection (exp. 12 Pesukim).