A week or two before you plan on introducing solids, start thickening your child's baby food. If you are making your own baby food, you can do this by adding less water or liquid when pureeing. If you are using the jarred baby foods, make sure you are on stage 2 foods. Some stage 3 foods are also good, as long as they don't have a mixed texture (whole pieces of food mixed in with the puree). Don't go there -- yet. You can also increase thickness by adding cereal to baby food or adding freshly pureed baby food to the jarred variety.
When to Start
In general, most babies are ready to start on solid foods around the age of eight or nine months. However, it may be later for your baby, especially if they were premature. You will know if your baby isn't quite ready yet if he refuses, gags, chokes, or coughs a lot when you try to give him solid foods. This is nothing to worry about. Just hold off for a little longer on the solid foods and try again later. Just take things a little slower and consistently offer them safe foods that they won't choke on.
Some babies may be ready sooner, though it is not recommended. Of course, it is always your choice and you will know when your baby is ready or not.
What the First Food Should Be
One of the best foods to introduce to your child first is something like Gerber Puffs. They aren't necessarily for the nutritional value, but for teaching your child how to handle a piece of solid food in his mouth. They work well because they are hard and crunchy at first, allowing your baby to realize that he has a piece of food in his mouth and to be able to keep track of it. However, they will dissolve very quickly in saliva, so if your baby doesn't chew and just tries to swallow it, you know that he won't choke. They can be easily handled by the baby himself and can be broken up into smaller pieces if you are still feeling nervous.
Many parents think that it's better to start infants off with something soft, like eggs or bananas, but this deprives your child of the opportunity to learn to chew. Because these foods are so soft, babies have a hard time figuring out where exactly they are inside their mouths and will usually just swallow them.
Once they get the hang of the puffs, try introducing other solid foods that dissolve quickly: Townhouse crackers (not Ritz), graham crackers, cheese puffs, and Baby Mum Mums. As your baby is able to handle these foods well, you can introduce other soft foods, such as bananas, noodles, cheese, breads, and over-cooked veggies cut into cubes.
- Once you begin introducing table foods, offer one per meal. Then slowly increase the variety of foods until they are managing more foods.
- Continue to steadily increase the thickness of the baby food as you progress.
- Carefully monitor all new foods. Some coughing and the occasional gag is normal. However, if you are seeing this frequently, you may be trying to give them a texture that is too difficult. Wait a week or so before trying to introduce it again, and then proceed slowly.
- Discuss persistent gagging and choking with your child's doctor.
Information taken from: http://www.yourkidstable.com/2012/09/how-to-transition-your-baby-or-toddler.html