Water filling soil, spraying a layer on the surface of parts can check whether the surface is smooth, which is beneficial to coloring.
Toothpaste can be filled with a little oily thinner and then applied to the place where there is no meat. It will shrink when it dries, so it's better to apply it several times to fill the meat. You can use it.
AB fill soil is highly recommended. AB fill is divided into two pieces. Take the required amount, mix the A fill with the B fill, and fill it in the place without meat like plasticine. When it hardens, it will be completely integrated with the parts.
As for the brand, I recommend Tamiya. The price may be expensive, but the things are absolutely good, which can save novices a lot of trouble.
How to carve is the patent of the great god. For example, if the carving of a part is too shallow, it can be deepened, or if hg is too simple, it is a light part. You can add carving. It looks beautiful, but it's too much trouble. I don't usually do it.