Worksheets that are neat and tidy are easy to filter.
It will be easy to filter the data in this worksheet; it's neat and tidy. If worksheet data is not already tidy, it's a good idea to get it in shape before you filter. Keep these guidelines in mind when you prepare worksheet data for filtering:
Use headings The top row of each column should have a heading that describes the contents of the column, such as "Product Name" or "Employee Name."
Don't mix The data in each column should all be of one type only. Do not mix text in a column with numbers, or numbers in a column with dates.
Don't interrupt Data should not be interrupted by blank rows or blank columns. Individual blank cells are okay.
Keep separate The data you want to filter should be on its own worksheet. If that's not possible, it should be separated from other data by a blank row or blank column.