I don't have any other book recommendations, but let's look at that sentence again.
First, "remarks" is a noun here because of its placement. (Unless you are Yoda, you will usually place the verb
after the noun.) In general, any time you see an article ("the" or "a"), it will be followed by a noun or a modifier and then a noun:
The rain fell swiftly.
The acid rain fell swiftly.
The main thing I want to know is how she did it.
The sharp kick delivered to me under the table reminded me not to mention Dan.
(The subject-verb pairs are "rain-fell, rain-fell, thing-is, and kick-reminded. Note that in the second sentence, acid precedes the subject and serves as an adjective. In the fourth, we know that "kick" is a noun, not a verb, because it's after "the sharp" (article-adjective)).
If you start a sentence with a noun and it's not in a modifier, then it will be the main subject of the sentence, and whatever it does will be the main verb. So in our original sentence, we know that "remarks" is the subject before we even get to "by." Even if we didn't have "the" or "by," we could still tell that it was a noun, again because of placement:
Remarks can hurt people's feelings.
(Remarks-can)
One important difference between this approach and yours is that we don't really have to read the sentence first and think about what the main subject is. We should know automatically because of the structure. You don't wait until the end and then ask "What is this sentence about and what is that subject doing?" Rather, answering this question should be part of your reading process.
Let's do a few more. Again, find the main subject and verb.
The only thing preventing me from running away was the big pile of cash on the table.
The abundance of minerals in the earth's crust is replenished when plants decompose.
In my opinion, hip-hop is overrated.
Aside from his parents, no one else in the world knows what he achieved today.
If future generations of Americans decide to connect their computers directly to their brains, the world will change dramatically.
thing-was ("Preventing" can be a verb, but it's modifying "thing" here. If we stopped at "The only thing preventing me," we wouldn't have a sentence. We'd still be saying "Yes, what about it?" We need that main verb--was.)
abundance-is (Minerals isn't the subject because it came second and is in a modifier--"of minerals.")
hip-hop-is ("In my opinion" is an opening modifier, so "opinion" is not the subject.)
No one-knows (Again, "Aside from his parents" is an opening modifier. "He-achieved" is a second subject-verb pair here.)
The last one is tricky. "If" creates a connection between the first clause, in which the subject-verb pair is "generations-decide" and the second, in which the pair is "the world will." You could say that the second pair is the main subject-verb of the sentence, but that really doesn't matter as long as they are both correct on their own. Also notice that both verbs are followed by additional verbs that work with them--"decide to connect" and "will change." When identifying the subject-verb pair, we'll generally include these, making the full core of the sentence "If Americans decide to connect, the world will change."