You can use the configuration templates found in this repository to quickly get started with a complete Varnish configuration that offers support for most functionality. Start of by looking into "default.vcl" and taking the bits you need, copy it to your own default.vcl.
A set of configuration samples used for Varnish 5.0 with various features:
Common list of errors and their fixes:
There is already a newer version out: Varnish 6 VCL config template.