Your altar does not have to be paticularly big, or highly decorative. These are the basic things you will need to create your own altar;
A table, positioned traditionally in the north. The ideal size is held at waist high, and an arm’s length wide, but a smaller one won’t make a difference; it’s just easier to fit all you might want to on a bigger table.
An altar cloth, which can be just a plain cloth all year round, or different colors, matched to the season or sabbat. You should choose a cloth made from natural fibres, if at all possible. PVC has a time and a place, and this is neither.
Representations of divinity, like statues of the God and Goddess, or candles symbolising them. The left hand side of the altar is normally seen as the Goddess’ side, and the right hand side is the God’s side.
Representation of fire; candles, in the south of the altar, on the right hand side as they are symbolic of the God. You can put your athame here as well, as it also symbolises the God.
Representation of water; a bowl of water, in the west of the altar. This will be the Goddess’ side, and you can also keep your chalice here as it is symbolic of the Goddess and the womb.
Representation of earth; a bowl of salt, in the north of the altar, on the left hand side, as it relates to the Goddess. You can also place your pentacle here, and that doesn’t necessarily mean a small pendant. A large metal pentacle is ideal for keeping your cauldron on.
Representation of air; incense, in the east of the altar. This will be on the God’s side, as incense is also symbolic of the God, as is your wand, which you could keep here too.
Personalisation; place things on your altar which have meaning for you. This could be part of a spell, or just something you have seen and picked up while outside walking. It could be something you’ve written, or a piece of writing which you have really liked. There are no hard and fast rules here; you work with things that hold personal meaning to you.
Additionally, some people dislike having others touch things on their altar, as they feel it’s an intrusion, and it introduces “outside energy” into their tools. You may not feel this way, but you should be aware that others might, and remember to ask before you try to touch anything. Above all, remember that this is meant to be a sacred space, and treat it with respect.