Putting kana into practice begins with writing the words learners meet earliest. Foreign loanwords are rendered in katakana by mapping each syllable to its closest kana. The country name アメリカ (America) becomes ア + メ + リ + カ, and フランス (France) becomes フ + ラ + ン + ス. Place names written in hiragana follow the same principle: Tokyo is とうきょう, with each mora represented by its corresponding kana, including the yōon きょう as a single syllable.
An important convention is that grammatical particles, even when their pronunciation happens to match a katakana character, are always written in hiragana. The particle "to" is therefore written とは not トは, because particles are native grammatical elements rather than foreign words. This rule helps readers instantly recognize the role of small words like を, は, and が in a sentence, since these grammatical markers always appear in hiragana no matter what.
Several katakana pairs are notoriously easy to confuse, especially in handwriting. The pair シ (shi) and ツ (tsu) trips up many beginners: シ is written with two strokes that both flow toward the left, while ツ begins with one short leftward stroke followed by a longer curve to the right. The pair フ (fu) and ウ (u) is another hazard: フ is a small hook that curves back to the left, while ウ extends with a longer stroke bending downward. Finally, the characters ソ (so) and ン (n) both look like small marks; the difference lies in whether the stroke leans or curls. Practicing these distinctions carefully at the start saves a great deal of confusion later on.
One final concept to internalize is the mora. A mora is a unit of sound that Japanese uses to count syllables, and it does not always match the number of kana written. The word とうきょう contains four morae: と, う, きょ, and う. Although きょう looks like two kana, it represents one mora. Understanding this distinction is essential for pronunciation, for using dictionaries that list words by mora count, and for mastering rhythm in spoken Japanese.