Here are a few hints:
Katakana "ru" at the end of a word almost always comes from "r" or "l".
Example: "inisharu" is from "initial".
Katakana "to" and "do" are usually used for "t" and "d" respectively.
For instance, "Dragonball" (as in "Dragonball Z" is "doragonbooru" in katakana.
The vowel "a" is sometimes used for an English "uh" sound.
Example: Sunglasses are "sangurasu".
The vowel "a" with length mark (Romanized as "aa") is sometimes used for the sound of "er".
Example: An internet server is "saabaa".