missing "but"  -- (MW) The untranslated word joins phrases in an adversarial way and is usually translated as "but." Since it always falls in the second position, translating it as "however" often captures its feeling better.

Again  - "Again" is from a word that means "back," "backward," "contradiction," "again," "once more," and "in turn." It means "again," when someone repeats themselves and "contradiction" when it is something opposed, which is indicated by the word above.

I -- This is from the first-person, singular form of the following verb.

tell -- The word translated as "say" is the most common word that means "to say," and "to speak," but it also means "to teach," which seems to be the way Christ uses it more frequently. It also has many ancillary meanings such as "to count" ("to number" or like we might say, "to recount" a story) or "to choose for yourself." Christ usually uses this word to refer to his own speaking or teaching.

you,  -- The Greek pronoun "you" here is plural and in the form of an indirect object, "to you," "for you," etc.

It -- This is from the third-person, singular form of the verb.

is - The verb "is" here is the common form of "to be" in Greek. It means to have a certain characteristic or remain in a certain condition. It also equates terms or assigns characteristics.

easier  -- The word translated as "easier" is a compound word. It means "easy" and "easy work." It is an uncommon word, appearing only seven times in the NT and only five times in the rest of ancient Greek literature. The prefix here means "good" or "better" because the word is comparative. The base word primarily means "beating" or "fatigue". So the sense is "better fatigue", which has the sense of "less tiring".

for -- (IW) The expected word form here is either the dative or the genitive, both of which require a preposition to express in English. The genitive is usually used in a comparison.

a -- There is no indefinite article in Greek, but when a word doesn't have a definite article, the indefinite article can be added in English translation.

camel  - "A camel" is translated from a Greek word that means "camel." It is in the form of an object of the verb translated as "to go." However, in Aramaic, a similar word means both "camel" and "rope." In Greek, they are slightly different. There is also the idea that this could be a reference to the "needle" gate in Jerusalem. Here is a current list of articles discussing these ideas. The form of this word makes its subject of the "to go" clause because in Greek an infinitive takes an accusative object

to -- This "to" is added because the infinitive form of the verb requires a "to" in English.

go  -  - "Go through" is a Greek verb that means "to go through," "arrive," and "to pass through." It does not mean "walk."  It has a number of special meanings such as "pass" when applied to time. Its prefix is the same as the following preposition meaning "through." 

through - This completes the meaning of the verb. It is from the prefix.

the -- (IW) There is  nothing in the Greek that can be translated as "the" in the Greek source.

eye  - (CW) "Eye" is translated from a Greek word that generally means a "hole" or "opening."

of -- This word "of"  comes from the genitive case of the following word that requires the addition of a preposition in English.  The most common is the "of" of possession.

a -- There is no indefinite article in Greek, but when a word doesn't have a definite article, the indefinite article can be added in English translation.

needle,  - "Needle" is translated from a Greek word that means "needle." A different word for the needle is used in Luke 18:25 but the same word is used in Mark.

than  - The word translated as "than" usually means "or" but when used in a comparative, as here, means "than."

for someone who is -- (IP) There is  nothing in the Greek that can be translated as "for someone who is" in the Greek source.

rich  - "Rich" is from an adjective that means "rich," and "opulent." It very much has the sense of ostentatiously rich. Here, it is not used with an article as in the previous verse. It is the subject of an infinitive clause, like "camel" above.

to -- This "to" is added because the infinitive form of the verb requires a "to" in English.

enter -- There is nothing in the Greek that can be translated as "to9 enter" in the source we use today but it does exist in the source that the KJV translators used.

missing "into"  -- (MW) The untranslated word "into" means "into" a place, "towards" as a direction, "in regards to" a subject, and "up to" limits in time and measure.

the -- The word translated as "the" is the Greek definite article. The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those") than the English "the." See this article for more. 

kingdom  - The word translated as "kingdom" can be the region, the reign, the castle or the authority of a ruler. Christ does not seem to use it to mean a physical region, so its translation as "reign" or "realm" seems more appropriate. This is especially true because the "reign" of a king means the execution of his will.

of -- This word "of"  comes from the genitive case of the following word that requires the addition of a preposition in English.  The most common is the "of" of possession.

missing "the"  -- (MW) The untranslated word is the Greek definite article, "the." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those"). See this article for more. 

God. -- The word for "God" or "the deity" is used here. This is a change from the previous verse which referenced the "realm of the skies."