How to remember katakana characters

Some of the katakana characters look like something already familiar or remind you of a word. Here are some examples that I use.

The katakana character エ "e" looks like an "I".
The katakana character ウ "u" reminds me of a hanger.
The katakana character キ "ki" looks like a cross.
The katakana character レ "re" reminds me of the word rev.

Learning Japanese language

The best learn order for learning the Japanese language is: hiragana, katakana, and then kanji. Romaji is also sometimes used at first for non-speakers of the language.