The purpose of doing a test import is to identify and correct problems before starting an import of a large data set. Your successful test import will create a data map A file that contains information about how data from a source system corresponds to data in Microsoft Dynamics CRM. that you can reuse for your full import, or export and edit to include any mappings that cannot be done with the Import Data Wizard .
Do a test deletion before you delete the imported records.
Perform any required preparation in Microsoft Dynamics CRM and in your source files before doing a test import, including determining whether import or the wizard should create custom record types.
Create each test import in a separate folder, using the same names for each type of record in each folder. When you reuse a data map, your source .csv file must have the same name each time for the mappings from the data map to be used.
Use 5-10 records per record type.
Make sure the data in each record has relationships that are similar to your main set of data to import. For example, if you are importing contacts that are all associated with accounts, your test account file should contain all the accounts that are assocatiated with the records in your test contacts file.