Well when my daughter went into the hospital at a month old, the papers the dietician gave us, suggest rice cereal at about 4 months and then at 6 months to start fruits and veggies assuming your baby is formula fed, otherwise you start with meat. And you're supposed to start just one type of food at a time, for about 3-4 days before introducing another, and then you can keep adding, but that way if the baby has any problems with adding certain foods you know which food is causing problems. My little one is 3 and a half months old and we have started rice cereal with a more formula-like consistency. We only do this with her once a day from a spoon and then we put just a half scoop of rice cereal for every 4 oz of formula in her bottle before bed.
My friend got the go ahead to start her daughter on rice cereal at 2 and a half months old, because her daughter is showing signs of teething and now at almost 5 months old she is already starting fruits and vegetables.
Definitely ask your doctor for a chart at your next appointment or look online for dietician charts involving babies :)
Anyway I hope this helps. With the cereal thing, I do it from her bowl only once, sometimes 2x, a day because she doesn't want the rice cereal when she is overly-tired. And just wants her bottle sometimes. I would say just go with what your baby shows you he wants. Over time they start choosing the spoon more and more over the bottle.