If someone recognized that they had some level of prejudice against persons from India, what would you advise they do.
To be clear, I have friends of Indian descent, and I value them, but I also work with people from India and I'm afraid I find them more annoying than not.
It's good that you recognise your bias. Most, if not all people have biases. Few recognise them. Even fewer are willing to fix them. So kudos to you.
The best way to work on such feelings is with a professional such as a therapist. I'd like to remind you that there doesn't need to be anything wrong with a person to be able to benefit from seeing a therapist.
Seeing a (good) therapist can, and in almost all cases will make someone a better person because you get a (more or less) objective outside view that makes you question and explore your emotions, why you feel the way you feel, and help you figure out what you can do to change for the better.
That said, IMO, you could start here:
Firstly, you must realise (you very probably already know this, maybe you just haven't given it much thought) that there are all kinds of people from all countries, in all kinds of demographics.
Secondly, it's import to ask yourself what is it about most Indians that you find annoying? Is it their attitude? Is it their accent? Is it their culture?
Don't be ashamed if you find that your reasoning doesn't make sense or isn't completely rational. Feelings often aren't. That's okay.
Once you know what it is that you don't like about Indians, pay attention to it next time you feel annoyed by Indians. Are they really doing something that should annoy you? Or is it a false perception of yours? Recognising biases and catching yourself in the act goes a long way towards overcoming said biases.
You should also try to find like-minded individuals, or individuals that you look up to from the demographic in question and spend time with them. That'll help you realise that there are likable and admirable people within the group too, and help dismiss your biases against them.
I think it depends on what annoys you. I find myself annoyed by any kind of cultural tick. Phrases, mannerisms, cliches, tropes, all bother me to the extent that they are common and pervasive (in any culture).
But by far I see this the worste in youths. Highschoolers and undergrads are so painfully unoriginal. But, that's life. Better to focus your attention on people who you find unique and impressive than to worry about people who are still finding themselves.
All I'm saying is this - I've worked with people across many ethnic/cultural groups. If I can draw any stereotype, it's that the most unique, intelligent, and competent people are those in their 40s.
To be clear, I have friends of Indian descent, and I value them, but I also work with people from India and I'm afraid I find them more annoying than not.