Hmm. Please note that this will be from personal experience in reading novels. I am not Chinese and do not know the language or culture particularly well.
Brother/Sister - someone from the same clan/sect/whatever (generally, not always though) that the speaker is close to or wishes to suck up to.
Junior - Generally but not always a term of some respect/acknowledgement, used (generally) by someone in the same clan/sect/whatever or is friendly to the one being spoken to, where the one speaking has a higher status or more power.
Senior - term of respect, indicating that the person speaking is lesser than whoever they are speaking to. Not necessarily used to address people of the older generation, although it is sometimes the case. More often it is used to refer to someone from the same generation or slightly older who has more status/power than the speaker. Not necessarily used to refer to someone from the same sect/clan, although it is often so. If not, it may be an attempt to suck up to the person being spoken to, or an acknowledgement that the speaker is weaker/less status than the one being spoken to.
Elder - Term of respect, used to refer to someone of high (but not the highest) status, often of the older generation/two generations ago. Note that this is often an actual position in clans and sects, so it may also be used by anyone to refer to someone in that position.
Master - term of great respect, indicating that the one being spoken to is much greater than the one speaking. Generally only used by students to their masters. Note that this isn't used in a simple relationship like an elder teaching juniors in a sect, but more an inheritance situation where an elder is passing on much of his skill and knowledge to a single disciple.
Disciple - Term of acknowledgement, speaker is the master of the one being spoken to.
Dog/Trash - This should be obvious, but a derogatory term, meant to indicate that the speaker is much higher than the one being spoken to, either as a statement of fact or as an insult.
Note that depending on context pretty much any of these can be friendly or an insult.