Migration to Magento 2 involves four components: data, extensions, themes, and customizations.
To have a successful migration, use the following guidelines:
Build and test Magento 2
To prepare for the migration, make sure you do all of the following:
1)Set up a Magento 2.0 system using a topology and design that at least matches your existing Magento 1 system
2)To provide redundancy in the event of unexpected issues, we advise you to replicate your Magento 1.x database and use this Magento 1.x data for your migration
3)Install Magento 2 on a system that meets our system requirements.
First of all Make a full backup of your Magento 1 store including all files, folders, and the database.Then Create a clone of your Magento 1 store. Do not use the live store for the migration process, more you can find here, Magento 1 to Magento 2 Migration. A complete step by step guide.