Ok, I'll give it my best shot. I'll try to keep it objective, but my opinion of meaning might slide in from time to time. Let's use the following tracing board that I simply looked up on google:
Ok, let's see if I can break this down...
The border: You'll notice that along the border are the letters "N, S, E, and W". These represent the directions North, South, East, and West. In Freemasonry, "travelling" west to east is symbolic of seeking light (knowledge) since the sun rises in the east.
Now then, going from top to bottom...
Acacia plant: The Acacia plant is mentioned in the legend of Hiram Abiff as growing above his grave. Symbolically, it represents to purity and endurance of the soul, as well as resurrection and immortality. (note: nowhere in the legend of Hiram Abiff is there any suggestion that he was resurrected to life. As far as I know, the resurrection and immortality meaning refers only to the soul)
Below the acacia, we see a coffin with various symbols on it, once again referring to the legend of Hiram Abiff. In the legend, Hiram Abiff was the master mason of King Solomon's temple. He refused to give all of his knowledge of masonry to three fellowcraft masons, and they killed him for it.
Going from top to bottom on the coffin itself:
The common gavel: Symbolizes governance and teaches masons to hammer their rough edges smooth (basic metaphor for correcting our flaws).
The compass: Multiple meanings; teaches masons to circumscribe their desires, also reminds masons the keep themselves connected to the center of their lives.
The trowel: (at least, I think that's what it is... it's the only working tool not clearly found elsewhere on the coffin, and I can't think of what else that symbol could be) Reminds masons to spread the cement of brotherly love and friendship.
Page of Hebrew writing(?): I'm not as familiar with hebrew, I've read a couple explanations, but I don't have enough of a grasp of it to provide a simple explanation. I'm pretty sure it relates to Hiram Abiff's name, and the year that he died. Not sure on this one, if it's important, let me know and I'll try to find out more.
Skull and crossbones: Another symbol of the death of Hiram Abiff. I'm not sure if they are meant to have additional meaning. I've always thought they were part of the coffin with the symbols of freemasonry added around them.
The number "5" (at three places on the coffin): This represents the 5 points of fellowship. In masonry, these points are the foot, knee, breast, back, and mouth-to-ear. I've heard that there are lessons behind each point, like the foot represeting how far we are willing to travel to help our fellow man, or the mouth-to-ear represeting how we should not speak poorly of our fellow man in his absence... but I don't know these stories well enough to fully explain them. I can research them further if you like. As far as I know, the three occurences of the number 5 refers to the three degrees of masonry, and that the 5 points of fellowship apply to each degree equally.
The arch, columns, and floor: These are a representation of the sanctum santorum (sp?), which was the highest chamber in King Solomon's temple. According to the legend, Hiram Abiff died before completing it. When a masonic lodge is opened on the third degree, it is done so in a place representing the sanctum santorum (sp?).
The common gavel: Same meaning as above, not sure if there is additional meaning to it's second appearance above the other working tools.
The level: As I believe I mentioned earlier, the level (along with the plumb line) teaches masons to meet "on the level" (treat each other as equals), and the plumb line that is attached to the level reminds masons to be upright before man and toward god (upright used as a metaphor for honesty and integrity... the opposite being hunched over - ever seen a movie with a villain that is always hunching over and sneaking around?
The 24" guage: Symbolizes the day, broken up into 24 hours, and reminds masons to divide their time between work and rest, service to god and service to their fellow man.
The square: Reminds masons to square their actions before god, and toward their fellow man.
I think that about covers it... apart from the sections that I'm not familiar with enough to adequately cover. If you want to know more, I'll try to research them further.