For all tech companies in general. This is the best guide out there: Tech Interview Handbook.
This is the trajectory you should follow for Google.
Year 1:
Atleast one CS & Math core course
Take One OOP language
Understand formal logic
Version Control
Learn debugging
ECA:-
CS Clubs or societies (WICS, ACM, NSBE etc.)
Hackathons & programming competitions
Web/Mobile App Development
Open Source Projects (Google summer of code etc.)
Online competitions (Google Code jam, hash code, topcoder etc.)
CS Project outside of classroom
What do 1st & 2nd year students put on their resume?
Work Experiences -> Any Experiences
Student Organizations
Hackathons
Coding competitions
Class Projects
Year 2:
Data Structure & Algorithms
Proficiency in atleast one Programming Language [Java, C, C++, Python, JavaScript, Go]
Personal/Collaborative CS Projects
Year 3:
Strong Knowledge of Data Structures & Algorithms
Solid proficiency in more than one Programming Language
Strong Knowledge of Operating Systems
Some software design
Discrete Mathematics
Industry-level Internships (Google internships open around mid September)
Year 4:
Confidence in what we've discussed so far
Industry level internships
Polished Resume
Focused time on interview preparation
Advice/referrals from former intern & alumni
Resume Examples
_________________________________________
Software Engineering Internship:
Intended graduation month/year
Relevant coursework
Projects and classes focused on data structures & algorithms
Extracurriculars to gain technical experience
Coding proficiency and experience
_________________________________________
Software Engineer, University Graduate:
Intended graduation month/year
Relevant coursework
Advanced projects/dev experience in multiple languages
Extracurriculars to gain technical experience
Industry-level coding proficiency and experience
_________________________________________
Resources:
Careers On Air
Google Students
techdevguide
Google Students Youtube
Build Your Future with Google
Google Virtual Career Fair