E? Nani? Romaij is the easy part! :) Romaji is what you already know. Then cometh the nightmare called 'Kanji'. There's no trick to memorizing Romaji: it's just letters; you have to learn the words like any other vocab you drilled in your life. At least with Kanji you get to make some visual associations.
Basically, for people who start out with Japanese, and use a roman alphabet as basis,Romaji are almost a must, at start; otherwise you get completely overwhelmed!
I'm a good two monts in my studies now, and just learnt hiragana. Soon I will add katakana to that; and then on to the ever dreaded Kanji.I hope to leave Romaji behind me, though, as soon as is humanly possible. So, likewise, I suggest you invest not too much time in finding clever ways to memorize Romaji; for one, because they're really aren't any. :)