See the first and the most important aspect about dealing with the objective type questions is maintaining a good confidence level. The simple logic behind this is that it brings a positive approach out of you towards initiating the first and basic steps to solving and answering the question correctly even if you are not sure about what the correct answer is. Patience and confidence ,many people might think i am boasting ,are the priliminary requisites to go for objectives.
Objectives are generally classified in two broad categories:
1) Questions that are meant to test specifically and only your knowledge.
2) Questions that are made to test your intellect and have very less to do with your knowledge of concept.
Often both of these types are equally distributed in a full objective question paper.
Regarding the first type of questions ,picking the correct one is a bit sticky job but still you can try to detect a hint from the question that might assist to catch the odd one out ,you can go for it. It works in most of the cases including but not limiting to CAT ,IITJee etc.
It often applies to questions related to Chemistry, History , Geography,Economics and related subjects.
Coming to second category of objectives that are meant just to test your intellectual skills ,one can try to find the most appropriate option among the choices (can just make a wild guess if nothing works) and then move to the question trying to fit that choice so that it works the question out.
This things often works for mathematics ,accounts related questions.
In the end a quote that may look a myth but true from my experience.
If you have studied the subject and you come across a question that you know you can't solve, answer sometimes just comes from instinct within if you are in perfect mood and high confidence.
This is no guarentee although.
All the Best (hope this helps)