I used to cast circles fairly often. When I did so, I was a bit overly dramatic and ritualized, because it helped me to get into a higher state of consciousness by operating in that fashion.
Firstly, I would take all the tools I intended to use in my ritual, and place them in the center of the circle. I did this so that I wouldn't be forced to break my circle to get something, or to stop in the middle of my circle casting because I forgot item number 26.
Please note, the following is a description of a full out circle for me. I used various shorter forms which included what is inside the description.
When outside, I would place 5 tiles on the area I wanted to use (I always used the same spots, and sometimes left the tiles in place if I intended to perform the ritual over a period of several days. I would then place 5 plates on the titles, then 5 bowls on the plates, and five stones on the plates associated with the particular element of the bowl, plate, and tile. (Each bowl, plate, and tile was marked with a sigil smeared with my blood.) I then would place a candle in each bowl, attach a stick of incense to each candle, toss some salt into the bowl, and fill it with water to slightly below the lip of the candle. I would take several large stones/crystals, and place three, going in a counterclockwise fashion usually, between each of the four tiles, making a circular pattern.
Then I would walk around the circle with a bag of dirt that I would sprinkle/pour in a circular fashion around this circle, until it was all gone. I would go around lighting all the incense, then all the candles, and so forth.
When I got done, it was a massively large effort, that usually took about 45 minutes to set up. Which is usually why I did the whole thing only on highly important matters, or whenever it felt like it was necessary. Sometimes I simply used the tiles, bowls, and plates, sometimes I just used the dirt, sometimes I just used the stones, other times I used different combinations of them.
It really depends on what you have available. But unless you want to kill the grass, I wouldn't use salt to make a circle outside. There is a reason why enemies in times of war would burn down homes and salt the ground. ;)