I hated grammar in fifth grade. I didn't know what the teacher was talking about when she talked about adverbs modifying adverbs or adjectives... In junior high school, it seemed like something only the girls were good at and so it went, until high school. But this isn't about me, except to show that if grammar is tough for you, you are not alone. I too was once a 99-lb. grammatical weakling.
After thirty years of teaching Spanish, I am convinced that most students need a class in English grammar before they should be allowed to study Spanish. As a Spanish professor, I get a bit annoyed when I hear people justify taking a foreign language on the grounds that it will improve one's knowledge of English. After all, the Spanish language is not an auxiliary to the English language, and certainly not to an English department.
For almost all of the past 30 years, I've begun with a quick overview of the parts of speech, so that when speaking of nouns, for instance, I don't have to use long circumlocutions as if the four-letter word noun were as dirty as a few other four-letter words. By learning some basic terminology about how to talk about language, teacher and student will be on the same page. Students will ask intelligent questions and be able to identify their own areas of difficulty if they at least know how to identify the types of words they don't understand.
Let's start with an analogy from science. There are many types of orchids (around 25,000 so I understand), and each has a name. There are far more words in most languages than there are types of orchids -- but they each can be put in one of nine boxes, for the sake of classification. Some words may wear two hats, and function as a noun and a verb; for instance book, the noun, is something you read, but "to book" is a verb, meaning what police do when they arrest someone -- "Book 'em, Dano!" -- or, according to a slang expression somewhat out of date, to run off very quickly, either in flight from or in haste toward -- "When we heard they were gunna bust us, we booked it!"