To talk about names is Waiting for Godot is to open one giant can of worms. We’ll just go one worm at a time. "Godot" has the obvious association with "God," a fact that’s been utterly beaten into the ground by now. "Pozzo" sounds like "Godot" and "Bozzo," so it’s a strange mix of God and, well, a clown – that’s tragicomedy for you. The nicknames "Gogo" and "Didi" also remind us of Godot. The name "Lucky" leads us to ask the ever-popular question, "Is Lucky lucky?" Vladimir and Estragon each take on a third name with "Albert" and "Adam" respectively. You can search us to come up with something for Albert other than it’s arbitrary (and therefore irrational and absurd) and makes another dual pairing with the name Adam, which itself is biblical.
Costuming is not explicitly stated in the script, other than the use of bowlerhats and boots. However, in stage productions, Vladimir and Estragon are usually dressed like vagrants, reminding one of vaudevillian characters like Laurel and Hardy. In fact, we repeatedly see this slapstick quality to Vladimir and Estragon’s banter (like when they trade bowler hats or play with Estragon’s boots).
As you’ve probably heard by now, Waiting for Godot was originally written in French and then translated by Samuel Beckett himself into English. Beckett was Irish, so we hear a good deal of colloquial Dublinisms like "your man" and "I’d like well to hear him think." This adds to our vision of Vladimir and Estragon as everyday men, just some random guys on the side of the road, not philosophers or great thinkers.
Lucky’s one monologue undeniably represents something other than the everyday, colloquial speech we’ve gotten used to in Waiting for Godot. We talk about this speech to no end in Lucky’s character analysis if you’re interested in the details.