Always sow seeds in fresh, good-quality seed compost. Never be tempted to reuse old compost or use garden soil, which is too heavy and might contain pests and diseases.
There's no need to sow the entire packet of seeds. Most seeds will germinate, so only sow one or two more than you need in case of loses.
Write the name of the plant on a plastic label and pop it into the pot after sowing. This will help you remember what you're growing.
Seeds will germinate more quickly if pots are put inside a heated propagator. Don't worry if you don't have one. Put a plastic freezer bag over the top of your pot, secure with a rubber band and put on a sunny windowsill.
Pot seedlings on once they're around 2cm tall. Loosen the compost, gently hold a leaf (but never the stem) and lift from beneath the roots with a pencil. Place the seedling in the centre of a small pot filled with multipurpose compost and firm gently.