The advantages of card style teaching materials are numerous - portability, ease of access, no mechanical problems to name a few! Each teacher will no doubt have many ways of using flash cards. Here are a few suggestions for basic use.
1.

Using the picture side only:
Teachers can use the picture side to teach words in Japanese. Primary or junior secondary students in particular find it easier to memorize basic words with the help of a visual stimulus. Some cards can also be used to teach sentence making. For example, the teacher can show the cards [もういちど] and [みてください] together. Giving a wider context can make it easier for students to memorizethe phrases.

2.

Using the kana side only:
The teacher can use the kana side to teach students to read Japanese - the cards actually work as hiragana/katakana flash cards. Each kana word has the pronunciation in romaji to assist with reading if necessary. If not, this can easily be whited out.

3.Using both sides:
By using both sides, the teacher can integrate the students' learning of new words with reading of script.
4.Reducing the cards:
The cards can be reduced for a number of uses. Students can be given a set of hand sized picture/word cards to carry with them and use as a vocabulary learning aid. The picture and kana cards can be used to play a variety of group card games such as Karuta and Concentration.
5.Enlarging the cards:
The cards can be enlarged and put on the wall as posters to expose students as much as possible to Japanese script.