Some of the many symbols in The Glass Menagerie that hold the most significance serve to illustrate the inner traits of the characters. 

The symbol of perhaps most importance in the play is the figurine of the unicorn in Laura's glass menagerie. The unicorn, as a mythological creature, does not belong to our common, real world. Laura is that unicorn; she is not fit to live in the real world. Moreover, her disability makes her walk and behave in a unique way, much like the unicorn's horn makes him unique. The fact that the unicorn is made of glass is allegorical to Laura's fragile nature, which is prone to be shattered should anything rough happen to it. Therefore, when Jim and Laura accidentally bump against the menagerie, making the unicorn fall and break the horn, Laura's explanation for it was very much like explaining how she feels at that same moment with Jim: finally, normal.

LA U R A [smiling] I'll just imagine he had an operation. The horn was removed to make him feel less - freakish !

[They both laugh.] Now he will feel more at home with the other horses, the ones that don't have horns. 

The fire escape is mentioned quite a lot in the stage directions as well as it is referred to in the play. It serves as the constant foreshadowing Tom's own escape from the house. It also serves as the reminder of how Tom's father also left the family. Before the abandonment issues occur, it is in the fire escape landing where Tom retires to smoke and think about the things that really matter to him. It is his personal escape mechanism. In all, the fire escape is precisely that: the way out the door and forever.

I descended the step of this fire-escape for a last time and followed, from then on, in my father's footsteps, attempting to find in motion what was lost in space .

The larger-than-life photograph of Tom and Laura's father still remains as a central object of decoration in the Wingfield home. He, who abandons the family, is continuously remembered through that picture. This is an obvious symbol of the inability of Amanda to let go of the past and move forward. It is explained to us the following way

There is a fifth character in the play who doesn't appear except in this larger-than-life-size photograph over the mantel. This is our father who left us a long time ago [...].The last we heard of him was a picture postcard from Mazatlan, on the Pacific coast of Mexico, containing a message of two words - 'Hello - Good-bye!' and no address.

The name "blue roses", which is the nickname that Jim O'Connor gives Laura when they are in high school is symbolic of Laura's unique nature, much like the unicorn is also a symbol of her. Blue Roses was meant to be the word "pleurosis", which is a condition that Laura develops in high school. However, the delicate nature of a rose of a mythic color is embodied by Laura's own delicate and unique personality. It is also a symbol of how Jim did pay attention, and cared about, Laura, after all. 

The candles used during Jim's visit reflect the family's inability to pay utilities, hence, being only able to find their way through the feeble light of candles. The Wingfields do not seem to be able to keep up with the real world, even with their bills. Hence, when Tom wants Laura to blow her candle he is both hoping for them to, one day, catch up, and for her to just leave his memories, and sadness, for good.