After sucessfully tracing your bitmap, it will often be best to load the enhanced metafile into a vector file editor. Many improvements can then be made.
Although a lot of bitmaps will Trace well, some will give poor results, and editing can often save these files. The one type of bitmap which will give bad results, are those in which colours have been represented by dithering (lots of small dots of different colours). A bitmap editor can be used to preprocess bitmaps to get better results.
The more complex the sprite is, the larger the vector file, and the longer Tracing will take. To start with try a simple bitmap and then as you get a feel for the program, build up to more complex images.