What Level Should I Reach Before Using Manga to Help Me Learn?

Often times, you can take the wording you’re unfamiliar with, type it into a web search engine, include the word “grammar” after it, and get some useful results. It’s something you get better with over time.

Starting with something you’ve read in English helps (as is your case with ニセコイ). If you still own the comic in English, you can use that as a reference to confirm your understanding. But beware that this is a useful crutch and that translations intended for an English-speaking audience are not always going to accurate to what’s going on in the Japanese. (I used this reference method for the first two volumes of 俺物語!! before I was able to start referring to the English release less and less.)

My first-ever manga that I actually read more than three pages of was one that (at the time) didn’t have an English release, but I’d seen the English-subtitled anime adaptation of the material. That means I had a general idea of what to expect. It was a text-dense manga (ご注文はうさぎですか?), and I was translating four panels per day. I spent over half a year working my way through it, and often wasn’t sure of my understanding. The important point is that I forced myself to get through four panels per day, no matter what (except for when my computer died and I had no way to continue for a while).

What I found helped me make the most progress early on was to join the Absolute Beginner Book Club. This allowed me to read along with others at an enforced pace, and I was able to ask questions and get informed answers from more experienced learners who were reading along.