I'm not an electrician nor do I play one on TV. But this is what I would tell you.

1. the grounds need to be tied together, then a pigtail connected to the green screw on the switch(es).

2. the neutrals are not tied together in this picture.

3. the left switch is most likely a switch loop. As it is now, nothing is going to happen. There is no hot here, just the loop of wire that goes to the light. You need to tie the white neutral to the other neutrals and add a black hot. Two blacks, one on each side of the switch. This will switch the hot to the light.

4. that middle switch has both (I assume) the power line hot and neutral and the switch loop for the second lamp. As soon as you turn on the switch, you are shorting the power line and tripping the breaker. You need to determine which is the power entering the box and which is the switch loop to the lamps. Then bring the power hot black to the middle switch, a black jumper from this switch to the left switch. Then the black switch loop to the bottom of the middle switch. And tie all the neutrals together unswitched into the back of the box.

And a real electrician will probably say I've been smoking the wrong stuff again...

Need to figure out if the sconce that doesnt work connects at the other sconce or if the end of the wire is just in the wall somewhere. If the wire is not connected to the circuit it wont work no matter what you do.

Neutrals should all be tied together. Grounds should all be tied together, and the switches need a spare wire each to attach to the ground also.

Your hots are where the action takes place. From what I understand, you have two switches each operating separate lights. You need to find which hot is the power source. Wire nut that with two spare hot wires running to each switch. Then you need to hook the hots from the lights to their separate switch.

When its all done you should have 3 wire nuts in your box.

The problem is that those white wires may not be neutrals at all. You just can't go wirenutting things together because they are the same color.

According to OP description All of the neutrals were tied together in a wing nut and left to the side. none of them should be a hot. I do understand you need to look at what you have in the box before you start messing with it, and whites can be hot (hopefully labeled).

J, if you cant figure it out, it is worth getting a pro involved. I personally suspect the wire from the sconce that doesnt work is hidden in the wall.

He also stated that the circuit didn't work before he took it apart which could likely mean that some other harryhomeowner already screwed it up.

One sconce out of two did not work. And the other separate light (foyer) was working as well.

Put the wires in the switch box back the way they were when both switches turned on a light. Consider that the second sconce was a recent add-on, and that the other end of the wire is up in the attic waiting for someone with talent to fish it into the other box. (Either the sconce that was working or the switch box will work.) It seams clear that whoever hung the second sconce knew it would not work yet since they didn't even bother wiring it. You can also check the other sconce to see if the second set of wires is in there and just not hooked up on either end yet.

Another place to check is in the box behind the first sconce. The second may be daisy-chained off the first and the connection may have opened there.

Sorry Vith, you were right. I misread the original post.

Wow. Thank you all for the input. I wasn't sure how helpful a houzz post would be and it was! I think you are all leading me in the right direction. This weekend I'm going to try and investigate where the issue in the wiring to the second sconce is. Wish me luck and thank you again for all the great advice.