Arduino Learning

Hi, i have recently started working on Arduino and i have finished the basics but i keep wondering how can go from a rookie to a pro. What is the method i should follow to climb up the ladder systematically and effectively.

In simple words i need to learn advanced features when to use shields, which arduino to be used in which condition.

There is no "hard and fast rules" about what you want to know.

I often find its more about the project I have that defines what board I may want to use.

A CNC device often starts with at least a NANO and goes then to either a UNO or MEGA.

Simple flashing of strips of LED's can be done with as low as an ATTINY.

IOT devices start with lone ESP8266 all the way up to YUN's.

Depends on what you will need for I/O/ and power requirements and many projects don't need shields unless it is for a very specific function.

Best bet... Come to this forum and read all the posts and answers in Project Guidance and Programming Questions at least and more boards if you like. After a few months you'll know all the common mistakes and have seen enough of the advanced stuff to start getting it on your own.