Learn American English
Intermingling of culture inter-state, inter-national and amidst continents has given much scope for better living, trade, commerce and tolerance. English originated from England and has been affected by a lot of influences like French, German, Anglo-Saxon and Indo European cultures. As we look into the tree of English and its bifurcation, astounding facts emerge about similar words in Hindi, French and Spanish to name a few.
When you leaf through the pages of an English speaking dictionary or check through available books of English speaking, it is essential that when you speak, it should be legible and have all the components of inflections and appropriate consonacts. Phonology matters and getting the phonics of alphabets and vowels is a major step.
There are many advanced English speaking courses in India that allow you to experiment your tone in the accent based in UK or USA.
American English and British English seem to be the major branches with accents. They differ in pronunciations and spellings too.