Your question suggests you can speak english but you want improvement. assuming this, i'll suggest watching bbc, discovery and history channels. please remember we have no native speakers of the english language to interact with.for instance i don't know bengali but i've been staying in west bengal since my birth. the smattering of bengali i've, is the happy result of casual contact with bengali-speaking people, while, say, commuting to my workplace or asking which way to go, if i've to run an errand. my accent, my gestures and body language is in near-perfect consonance with the language, its speech rhythm and intonation. i have spent a lifetime learning english. but what has come down to us is second-hand, or, probably third. cut to the bones, the answer lies in speaking this beautiful language, approximating the native speech rhythm. hence, my suggestion.