Starting Solids and Safety Issues
It's not necessary to heat baby food, though some babies do like it that way. My guideline is that if you eat the food hot, heat it for your baby (like oatmeal or potatoes). If you eat the food cold, serve it to your baby cold (like pears or avocados). If you heat food in a microwave, which I don't recommend, make sure to stir it first to get rid of any hot spots and test the temperature before you feed it to your baby to avoid burning his mouth.
Spoiling FoodYour baby's saliva contains enzymes that will gradually break down food. If you serve your baby food straight from a jar and then return the jar to the fridge, you will find that it's a runny mess the next day. Your best bet is to use a cup or bowl and just get out the amount you think your child is going to eat. At first, this will only be about a teaspoon or so. If your child wants more, use a fresh spoon and add another teaspoon at a time. Don't add what's in the bowl back to the jar if there is any left. Just throw it away.
AllergiesThere are foods that cause problems with allergies more than others like milk and eggs. All foods should be introduced one at a time with a few days to a week between new foods in order to watch for allergic reactions or sensitivities, but there is no minimum age limit on when to start introducing new foods. If you introduce rice cereal at six months, for example, and find that it is well tolerated and there are no problems, you could introduce applesauce a few days later. (No need to stop feeding rice while you are introducing applesauce, though, since you know your baby handles that fine.)
Whether or not there is any history of allergies, be sure to watch for the signs of an allergic reaction (hives, difficulty breathing or asthma symptoms, swelling of the mouth or throat, vomiting or diarrhea and loss of consciousness), know how to respond and be ready to call 9-1-1 immediately.
ChokingThere are a number of foods that cause choking in babies and young children. Most of these won't be a concern until your child is older and starts taking lumpier foods. Still, be aware of what they are and be ready to deal with a choking emergency.
High Chair SafetyWhile your child is in the high chair, make sure that he can support himself and hold his head on his own. Always use the strap on the chair and make sure that the chair's tray is not too tight on your baby's chest. Make sure that you watch your child the entire time they are in the chair.
After each feeding, make sure that you clean the high chair. Some have trays that are small enough that they will fit in the dishwasher. This is the best way I've found to get all the cracks and crevices where pureed food likes to hide and spoil.
Introductory Solids Aren't MealsRemember, the first couple of months that your child is being introduced to solids is meant to be mostly a learning experience. Do not skip any feedings or reduce the amount of formula or breast milk your baby has been receiving. He still needs all the nutrition he's been getting from you or the bottle.
Don't Rush or OverfeedTake your time in the beginning and remember to pay attention to your child's cues and interest. Plan these times a couple of hours before or after a bottle or breast feeding and let your child take the time that he wants, whether it is a little or a lot. If your child seems uninterested, don't worry about it. Try again another time later in the day or on another day altogether. If your child turns away or refuses to open his mouth, end the feeding and move on to another activity. Don't feel like your child has to eat any set amount. Let him learn to respect what his body is telling him about his level of fullness and nutritional needs. Remember, babies have very small tummies.
Commercially Prepared Foods
Watch out for ingredients in commercial foods. First foods for starting solids will usually be called just that or have the number 1 on the jar. These typically contain a single ingredient, like carrots, and water. Foods for older babies contain many different ingredients. If you accidentally choose food for the wrong age group, you may inadvertently expose your baby to ingredients not yet introduced to his diet. This isn't necessarily a huge danger, but can certainly make tracking down a food allergy more difficult when you're attempting to isolate many ingredients.
Commercial cereals are usually labeled as single ingredient as well.
Rice is a great starter food for babies, but it's also a food that is often heavily sprayed with pesticides. For this reason, whether making your own cereal or buying commercial brands, I suggest going for the organic types.