A good rule of thumb is to serve pieces of food that are about the size of a pea to start. This will be easy for baby to pick up and eat and will also reduce any chances of choking. Let your child's unique hunger be your guide for portions (though start small to avoid wasting food)—serving sizes here are just an approximation. And know that the nutrition info here will vary according to which foods you serve.
For each meal or snack, choose 2-3 foods from a mix of food groups. Aim to include some fat in most meals and protein in many too.
Prepare the food, cutting into small pieces and/or mashing as needed to make the food easy to eat.
Start with small portions and allow more as baby indicates according to their hunger.
Notes
Store leftovers in an airtight container for 3-5 days in the fridge.
Many foods you cook for your family will work as baby finger foods—just be sure they are easy to squish between your fingers and the pieces are small and easy to chew.
Babies very normally make a lot of faces when they eat, so don't assume they don't like something just because they scrunch their nose!
Flavors and textures can take time to learn to eat, so continue offering foods in small portions even if baby hasn't liked them in the past—and make sure they taste good to you!