Use appropriate row height (not to much, make sure that data is easily comparible over rows/ clear overview)
Use appropriate widths (if possible wide enough to not wrap headers, not to big to leave much space between columns)
Numbers should be right-justified
Dates should not be right-justified
List-based filtering should only be used for columns of data that have less than 50 unique values, else use search based filtering.
column header justification should match the data justification.
aviod using embedded sections in columns (often cause of alignment/spacing issues)