Need to improve your british accent and seek help for it! The internet can be real source of information and prove to be very useful for the development of your accent. As a start, you can download British Accent Training Manual which would guide you about how to pronounce certain words with british accent.
For instance, in the words stupid and duty pronounce oo as ew. Unlike, in the American accent the word stupid would be pronounced stewpid .When we use standard English we lay emphasis on “Arh.” This happens with almost all the british accents but it is overstressed in RP. So, the words “bath”, “boath”, glass etc use of this vowel is made and in the rest parts of the Great Britain these words sound as “ah” and not as “Arh”
Avoid pronouncing T as American D and therefore duty would be pronounced as dewty and not as doody. You should also pronounce the suffix –ing with G and the looking is sometimes pronounced as lookin. In certain areas of Britain human beings are pronounced as hewman being and in other parts it is pronounced as yooman being but it can also be hewman bee-in.
The problem with so many people who endeavor to learn British English as the language is that they use pronunciation rules of their own language and they do not know the rules of british English and therefore face difficulties and often speak with heavy emphasis on certain words which is not needed.
Acquiring british accent is actually an asset which affects your job prospects. Not only this, it also helps you to effectively communicate with the employers, clients, staff etc. There are several schools which claim of teaching you the right British English accent but these schools focus mainly on the rules of grammar. So, it is better to go for audio training and learn the accent by yourself.