て form
Update: May 17, 2022 Correction. There are て-forms for adjectives, too, but this post addresses verbs only.
One of the stumbling blocks I had to learning Japanese was learning the て form of verbs. I guess I thought that if I just kept going that I'd eventually learn it. How wrong I was.
Learning て form is kind of like memorizing multiplication tables. You don't have to memorize them but it sure cuts down on a lot of time and work if you do.