Try to present your argument in as objective a way as possible. Avoid judgmental and emotive language, as this often reveals that you are presenting an opinion rather than evidence or a logical argument. Note, however, that whether a phrase or word is judgmental or emotive often depends on the context. It is best to avoid phrases like it is right, I believe, or I feel. Often these types of statements lead the writer into bias, a mistake that academic writing avoids. Remember to back up your arguments with sources and facts in order to give you credibility and a more objective tone.
For example, take a look at this sentence:
I feel that childhood obesity is unhealthy, and children’s eating habits are not right.
Note the use of I and the judgmental phrase, not right. Try to think of a way to portray the same information without inserting yourself or your opinion. For example, instead of saying I feel, ask yourself, "Is this a fact?" If it is a fact, write it as a statement:
Childhood obesity is unhealthy.
With this statement, you are stating a fact and removing yourself to maintain your authorial distance. Also, rather than saying their eating habits are not right (after all, who is to judge what is right and wrong in eating?), you can use statistics and valid sources to back up your ideas:
Two major causes of childhood obesity are poor nutrition and uneducated food choices (Fredricks, 2010).
Here you are giving information rather than giving a judgment. See APA manual section 3.11 for more guidelines for reducing bias.