My rule of thumb goes like this:

First week offer once per day at bubs happiest time
If they are handling that ok then offer twice per day (after around 1 week)
Then by 3 to 5 weeks 3 meals per day. I am more likely to make it 5 weeks

I also offer water in a sippy cup at each meal

Don't be in a rush to increase too quickly. If bub is having a few unsettled days then ease off on the solids.

Foods: I always try single foods for around 3 days in a row. This way I can tell if that particular food is agreeing with bub. Then if I know bub can tolerate a certain food I mix it up. To make rice cereal more palatable try mixing it with apple or pear.

Foods that I avoid initally: Berries, citrus and the main allergy foods

Currently I am investigating BLS and I will be doing a mix of the old puree method and BLS.

I hope that helped.