Jyates,
Some foods will be very liquidy, like pears. Others will just be smooth, like avacado and sweet potatoes. I use a food processor to puree most of my lo's foods. Foods like bananas and avacados I use a fork to mash. Many moms/dads use breast milk or formula to thin foods that are too thick for baby. I have been using water. As far as how thin to make it, you have to test that with dd. She will let you know if it's too thin or thick. When it's too thin, I usually add some cereal. Meat can be pureed as well, once it is cooked (boiling is probably the easiest way to cook it). 7-9 months is a good time to begin adding "lumps" to the food. Just puree a little less. Again, let your dd take the lead. If she's not ready for lumps, she will tell you and you will know for the next meal. Just keep trying once in a while to test it out. There's not too much of a right or wrong... just listen to your dd.
HTH
~Rachel