Although an arbitration generally means lower injury awards, the awards are usually more consistent and quicker to obtain. Your likeability is another factor. A sincere and honest claimant elicits more sympathy than one who appears abrasive, difficult or greedy. Similarly, the likeability of the defendant is important. If the accident happened because the defendant was drunk, a jury could award you more money in order to punish the negligent driver and make a point that drunk driving is not tolerated.
Juries tend to award more money to plaintiffs they like and punish negative behavior by defendants.
A jury is more likely to be sympathetic to your claim if they believe you are presenting an accurate picture of the accident and not exaggerating your injuries. Objective injuries can be verified in a way other than the client's complaints. For example, a broken leg can be verified by an x-ray. The jury can be shown the x-ray and see the fracture themselves. In these cases, the jury will generally believe that an injury exists.