Build from source or download telegraf (binaries forthcoming)
Run telegraf -sample-config > telegraf.toml to create an initial configuration
Edit the configuration to match your needs
Run telegraf -config telegraf.toml -test to output one full measurement sample to STDOUT
Run telegraf -config telegraf.toml to gather and send metrics to InfluxDB

Telegraf Options

Telegraf has a few options you can configure under the agent section of the config. If you don't see an agent section run telegraf -sample-config > telegraf.toml to create a valid initial configuration:

hostname: The hostname is passed as a tag. By default this will be the value retured by hostname on the machine running Telegraf. You can override that value here.
interval: How ofter to gather metrics. Uses a simple number + unit parser, ie "10s" for 10 seconds or "5m" for 5 minutes.
debug: Set to true to gather and send metrics to STDOUT as well as InfluxDB.

Plugin Options

There are 3 configuration options that are configurable per plugin:

pass: An array of strings that is used to filter metrics generated by the current plugin. Each string in the array is tested as a prefix against metrics and if it matches, the metric is emitted.
drop: The inverse of pass, if a metric matches, it is not emitted.
interval: How often to gather this metric. Normal plugins use a single global interval, but if one particular plugin should be run less or more often, you can configure that here.