You can make a judgement by weighing up evidence, looking at all sides of the argumant, and deciding in the light of all the information you have gathered, what is right or wrong. You are being judgemental if you allow your predjudices to make your decision for you without considering all of the above.

1) "In non-legal contexts, a judgement (British English) or judgment (American English) is a balanced weighing up of evidence preparatory to making a decision. A formal process of evaluation applies. A judgement may be expressed as a statement, e.g. S1: 'A is B' and is usually the outcome of an evaluation of alternatives. The formal process of evaluation can sometimes be described as a set of conditions and criteria that must be satisfied in order for a judgement to be made. What follows is a suggestive list of some conditions that are commonly required: - there must be corroborating evidence for S1, - there must be no true contradicting statements, - if there are contradicting statements, these must be outweighed by the corroborating evidence for S1, or - contradicting statements must themselves have no corroborating evidence - S1 must also corroborate and be corroborated by the system of statements which are accepted as true. One should be cautious in attributing, without a rigorous analysis, a rigid set of criteria to all forms of judgement. Often this results in unnecessary restrictions to judgement methodologies, excluding what may otherwise be considered legitimate judgements. For analogous difficulties in science and the scientific method see the Wikipedia entry on the scientific method. From the criteria mentioned above, we could judge that "It is raining" if there are raindrops hitting the window, if people outside are using umbrellas, and if there are clouds in the sky. Someone who says that despite all this, it is not raining, but cannot provide evidence for this, would not undermine our judgement. However, if they demonstrated that there was a sophisticated projection and audio system to produce the illusion of our evidence, then we would probably reconsider our judgement. However, we would not do this lightly, we would demand evidence of the existence of such a system. Then it would need to be decided again upon available new evidence whether or not it was raining. Many forms of judgement, including the above example, require that they be supported by, and support, known facts which are themselves well supported, and its negation must be shown to be unfounded, before it is accepted as well founded." Source and further information: http://en.wikipedia.org/wiki/Judgement 2) "Judgmental language is a subset of Style over substance fallacy and Red herring fallacies. It employs insultive, compromettant or pejorative language to influence the recipient's judgement. - Examples Surgeon general says smoking is harmful to your health. Nowhere in the Bible is said you shouldn't smoke. So who are you gonna listen to, some quack or Lord God Almighty? This argument combines judgmental language also with Non sequitur and appeal to authority. Conscription is the only working way to have a reliable and efficient army. We are far safer when we are defended by our very own sons than by some mercenaries, who will just fight for pay. Here the judgmental words are "our very own sons" (suppose you are childless or have only daughters?) and "mercenaries", which imply not only professional soldiers but rather soldiers of fortune. This argument is also a false dilemma: nothing implies that coercion and fear of punishment produces better soldiers than voluntarity, and that a professional army could not be assembled from the nation's own citizens." Source and further information: http://en.wikipedia.org/wiki/Judgmental_language

Being "judgemental" is juding someone without knowing all the facts. Like, sizing them up with just looking at them. Making a "sound judgement" is when you weigh your pros/cons, and study the facts. It is an informed decision.