What I did was quite standard: follow the study guide, Watch YouTube Channel of MArketing Cloud to see recorded webinars, follow online Webinars and do not hesitate to ask questions during the sessions, and I don’t know if you have a Partner Training account, but you can also do the online training dedicated to Marketing Cloud.

Last tips : I definitely recommand to test into an Org to be sure the understand the difference between Playbook/Automation/Journey Builder, List/Data Extension, Schedulled/Triggered Send, and the Connector.

Good Luck ;-)