How to create many new records without DML error in Salesforce?

Do not have DML statements or SOQL queries inside of your FOR loop
Try not to use SOQL or DML operations inside a loop
Try to bulkify your code and your helper methods
Can query large data sets
If you are working for 50,000 records, use Batch Apex
Streamline various triggers on the same object
Use Streamlining Queries and collections for loops
In order to avoid hitting Governor Limits, use limits Apex methods