"We can follow advice given by older people." "Advice" should be singular. "We can follow advice given by elder people" MIGHT actually be correct, I am not sure, but in 2014 it sounds strange and old-fashioned. "Can" is correct but unusual. It means "capability," we are able to follow that advice. You probably mean "We should follow advice given by older people." A good English sentence that uses "can" but means something slightly different is: "We can trust advice given by older people." To make the distinction clear I can combine the two: "Because we can trust advice given by older people, we should follow advice given by older people." Oddly enough it is also correct, in all of these examples, to say "the advice" instead of "advice." "We should follow the advice given by older people." Both are correct, both are natural, and the meaning is the same. It is also correct to say: "We should follow the advice of our elders." It is correct English to say "We should follow the advice of elderly people," BUT the cultural meaning is wrong. Strangely enough, the phrase "our elders" is respectful, while "elderly people" is very slightly disrespectful and emphasizes physical frailty, rather than wisdom. By the way, I'm don't think we SHOULD always follow the advice of older people! A famous saying of the 1960s was "don’t trust anybody over 30," but I don't agree with that, either.