Create export profiles of type:
EAV - mark all possible codes for export
Products - if you need to transfer images, make sure to set Export images setting to Yes
export only category.name option, all three category columns can cause problems in same import
Products Extra - mark all possible codes for export except CC
Edit EAV export, replace all Magento 1 class aliases in EA, EAX and EAXP codes with Magento 2 class names
Create EAV import profile on Magento 2, with the file from Magento 1 export
Import EAV data, make sure all attributes are correctly created.
if you have third party modules on Magento 1 which add attributes, make sure to install them on Magento 2 as well
if you do not plan to use any of those third party modules, make sure to remove their attributes from EAV export files
Create Products import on Magento 2, with the file from Magento 1 export.
probably will need to enable auto create category option and auto create dropdown values option.
if transferring images, make sure to copy the files into Magento 2 var/urapidflow/import/images folder
Import Products data, make sure to reindex all product related indexes.
Create Products extra import on Magento 2, with the file from Magento 1 export.
Import PRoducts extra data
Make sure products are listed correctly.