כתרומת גורן, which is the first tithe of the grain harvest as we know from Deuteronomy 18,4. When converting the harvest to something edible, preparing the dough, the Priest is also to receive his share from the first part of the dough. (Ediyot 1,2 as well as Shabbat 15)

וכי תשגו, by mistakenly committing an act considered forbidden under the rules of idolatry. What is written here also applies to inadvertent sins of a different nature which carry the karet penalty if committed deliberately.

את כל אשר צוה ה' אליכם ביד משה. All the sins referred to were committed inadvertently. The Torah simply means that the transgression of the single commandment not to commit idolatry is equivalent of the sinner having transgressed all the commandments G’d had commanded.

מן היום אשר צוה ה' והלאה, All the commandments in the Torah were commanded after the first 2 of the 10 Commandments.

ביד רמה מגדף, a reference to the commission of acts of idolatry, according to the plain meaning of the verse.

כי לא פורש, the type of death penalty had not yet been stated clearly.

ציצית, similar to Ezekiel 8,3בציצת ראשי , a bunch of fringes suspended like the hair of one’s head.

והיה לכם לציצית, the string known as tzitzit serves to attract your visual attention. The word is used in a similar sense to Song of Songs 2,9 מציץ מן החרכים, “peering” through the lattices. I have found that Sifri on our verse explains the word in similar fashion, quoting above verse from Song of Songs.

פתיל תכלת, our sages explained the reason for the blue colour as designed to remind the viewer of the blueness of the ocean, which in turn resembles the blueness of the sky reminding man of the throne of G’d’s glory situated in the celestial spheres.(compare Sifri on our verse).