Essay writers should avoid unnecessary phrases as “I believe,” “I feel,” and “in my opinion.” The grader knows whose opinion is being expressed and he or she does not need to be reminded.
WEAK: I am of the opinion that excessive self-reference may add a level of pomposity to an otherwise effective essay.
FORCEFUL: Excessive self-reference may add a level of pomposity to an otherwise effective essay.
Your statements are stronger and more believable when you say them with conviction and do not use self-reference. They appear more professional this way.