I started my daughter at 5 months, because I didn't know any better then. Started with rice cereal, then oatmeal, wheat, and barely cereals, then pureed veggies and fruits, one new food at a time every few days. She was eating 3 meals a day by about 9 months. Around that time she also started having serious issues with any wheat products - it gave her bad diarrhea and a horrible diaper rash. I had to eliminate all wheat products from her diet for about 9 months. I got extremely tired of spoon feeding her purees all the time. She continued breastfeeding until shortly after her 2nd birthday. At 4 years old, she is still a picky eater and often wants "help" eating her food (put it on the fork/spoon for her and put it in her mouth) even though she is perfectly capable of doing it herself. She is very skinny and I often have to fight with her to get her to eat a decent meal.
When I had my son, I waited until 6 months. I started with pieces of ripe banana, only slightly mashed, once a day. We did a little bit of baby cereal, but mostly pieces of soft cooked fruits and veggies, rice rusks, cheerios, and other adult cereals. I fed him with a spoon at first, but he learned to feed himself with his fingers very quickly. The only purees I fed him were applesauce and rice/oatmeal/barley cereal. I waited to introduce wheat products to avoid the issues my daughter had, which seems to have worked. He went to 2 meals a day about 8-9 months, and didn't eat 3 meals a day regularly until after 1 year old. By 1 year old he was eating exclusively adult table foods, cut up into small bits. He'll be 2 years old next month, and he already eats more and a better variety than his big sister. He feeds himself with a fork or spoon, and usually won't let me help him at all - I just put food in front of him and he eats it. He absolutely loves veggies, and usually finishes those first. He's still breastfeeding, and I plan to continue for about another year or so - we'll see how it goes.