These are 2 resources that will make your life easier if you are new to Marketo.
1. Icon Glossary
If you learn to read what the icons say, your life will be much easier. There are certain icons that you need to master, like the Marketing Activities icons. These have actually helped me teaching the story of what campaigns are doing.
2. Field Types.
Understanding the different fields that you can create in Marketo is also very important. This document is really useful when you are new to Marketo.
Special fields that you need to pay attention to are:
1. Boolean (previously checkbox)
2. String (a line for short text)