Start from the basics, if its object oriented, grasp the concepts (plenty of free videos on youtube). Setup the IDE for that language then move towards the basics of that language itself. syntax basics like how variables are declared, how methods are defined, how conditionals are used, operators, loops, basic data types including declaration for that specific language etc. Again many tutorials available online provided one must DO it and not just watch them. Create basic programs like string palindrome finding, list traversal etc. After you have covered the basics (and you will never think you have), create yourself a scenario of a product, think about its components and start building it. You may do botchery of the code but this is where your actual learning starts.
When you have worked with few programming languages, it starts mattering less and less if you need to work with another programming language, as it merely becomes syntax for your code. Now its where your focus rather shifts to the architecture of code, the design patterns used, performance sink holes, overall efficiency, load handling, fault tolerance, redundancy, data management etc etc (each of them have much more weight than learning another language). Hope this clarifies somethings.
