[Makino]

Hello! I am self studying Japanese through Genki. Right now I am learning the Ru and U verbs.. but how do you know when a verb is irregular?
Would memorazation be the best way to learn?

Also, I have a Japanese pen pal who is fluent in English, but I am not fluent in Japanese. I would like to write to her in Japanese, is there a sort of way to know how to make your hand writtian japanese look like a native Japanese

Lastly, because I live in a western home none of my family members speak Japanese. Because my goal is to travel to Japan and spend some time at a Japanese highschool, I would like to get as much practice as I can. What is a good way to "Japanize" myself so I can use the language constantly?

Thanks so much for your help!!!