Definitely take the 3 day online training course if at all possible. They also have several "Best Practices" articles.
Be sure to think about your naming and organization conventions in advance - here is a discussion item that may be helpful https://community.marketo.com/MarketoDiscussionDetail?id=90650000000PXXMAA4
Also, before you sync Salesforce with Marketo for the first time, try to have as many Lead fields have the same name as their mapped fields in Account and Contacts. Otherwise Marketo will create 3 separate fields for the same data depending on the Salesforce object that it comes from. Also, consider which Lead, Contact and Account fields you must have in Marketo and only make those fields visible to the Marketo Synch profile.
Good luck and have fun!