Visit a fruit market and collect as many local fruits as possible. If many fruits are not available, you can collect tomatoes and cucumbers (these are fruits, though we use them as vegetables). Make drawings of the different fruits. Split the fruits and examine the seeds within. Look for any special characteristics in the fruits and their seeds.
You can visit a library also to learn about this.

The fruits are collected and their seeds are studied such as:

Single seeds fruits: Mango and litchi.

Few seeds fruits: Apple and banana.

Multiple seeds fruits: Watermelon, orange, and lemon.

Types of leaves are also helpful in determining the types of seeds:

(i) Monocotyledons plant leaves are elongated slender with parallel veins.

(ii) Dicotyledons plant leaves possess distributed veins in a reticulated manner.

Extra information:

There are two major types of fruits: fleshy fruits and dry fruits.

Fleshy fruits are the fruits in which the pericarp and accessory components grow into succulent tissues, such as in eggplants, oranges, strawberries; and

Dry fruits are fruits in which the entire pericarp turns dry at maturity.

Fleshy fruits consist of

(1) berries, such as tomatoes, blueberries, and cherries, in which the entire pericarp and accessory parts are succulent tissue;

(2) aggregate fruits, such as blackberries and strawberries, which form from a single flower with many pistils, each of which develops into fruitless; and

(3) multiple fruits, such as pineapples and mulberries, which develop from the mature ovaries of an entire inflorescence.

Dry fruits include cereal grains, capsulated fruits, legumes, and nuts.