I started giving my son a few spoonfuls of rice cereal around 5 months, in the late afternoon, which seemed to work best for us. After he'd been eating the cereal for about a month, I added fruits and veggies one at a time. I can't remember which ones I did first, but his favorites were sweet potato, carrots, and all fruits. I made my own baby food when I could (soft stuff like bananas, easy to mash). I usually fed him his solid food right before my own dinner. I don't think it helped him sleep through the night, but then he was a pretty good sleeper by that point anyway. Oh, yeah, and I breastfed.