Text will appear in the main text style of your document, with the margins defined in the Table style.
Useful points to consider are:
Consider using a sans-serif font, such as Homerton (RISC OS) or Arial (Windows), which is easier to read.
Emphasise the title row and column, if any, by using bold text rather than capitals as this provides emphasis without lessening readability.
Grid patterns and background colours are also defined as styles. Remember that you can apply more than one style to an area if different attributes are set in each style.
You should define grids and background colours as separate styles to the main table style you are using for the table. This makes it much easier to change the look of the table without altering the basic way it is laid out.