Whether or not you have a paid support plan, as a Google Cloud Platform customer you have access to a large community of enthusiasts and experts to share ideas with and get support from. In many cases, the Googlers who write, maintain, and support GCP contribute to these communities, including Stack Overflow and Google Groups.
You have several communities to choose from.
Technical Questions: Stack Exchange, Stack Overflow, and Server Fault
For technical issues, try Stack Exchange sites. Stack Exchange uses a popular question-and-answer platform and it hosts a number of sites, including Stack Overflow and Server Fault. Stack Overflow is generally for developers and Server Fault is aimed at system and network administrators, but anybody can ask and answer questions on these sites. Each has a large, active user community that provides prompt, high-quality answers.
If you've never used Stack Overflow or another Stack Exchange site, you should take a look at Stack Overflow's guide to asking good questions for tips on the best ways to ask for help.
For more information about using Stack Exchange sites, including where to ask questions about specific GCP services, see Ask technical questions on Stack Exchange Sites.
Discussions: Google Groups
Google Groups hosts discussion forums where you're likely to find information like service status updates and release notes, and ranging from book recommendations to creative shortcuts.
For more information about using Google Groups, see Discuss Google Cloud Platform.
Report bugs and request features
GCP tracks known issues and feature requests on a set of issue trackers hosted on Google Code. You can access these trackers to report bugs and to request and vote for new GCP features.
For information about reporting bugs, making feature requests, and about how Google prioritizes requests, see Report bugs and request features.