Hello Ravi,
There are indeed many useful resources to learn C4C. Being a technical consultant, you can work on Cloud Application Studio (SDK/PDI) which off course involve learning different language. You can get some good documents on its dedicated SCN forum and You Tube.
Also you have an option to learn the integration of C4C with On Premise ECC/CRM. This forum has many useful document for same. I will suggest you to go through (or infact follow both the forums) to explore more on C4C
SAP Cloud for Customer Integration with ERP and CRM: How-to Guides and E-Learning
However to practice you need to have access to at least one C4C tenant.
Regards,
Chandan