Hello!
Thanks a lot for information, there are many helpful tools to improve the element quality. I was doing just with place nodes manually and smooth to improve it, but I learn how to use the other tools, some of them are easier to use.
Another tool that has been very helpful to improve the quality to me is spliting and combine elements, the result is kind that swap to edge but is easier to manipulate, I use them when place nodes manually is not enoough in some complex zones.
regards!