You want to have a flat surface to work on. (duh)
Angling is no problem at all, especially since glass plates are straight. All you need to do it line them all up properly and you will have a perfectly straight tank.
Always attach the panels on top of the bottom panel, never on the sides.
The side panels should come first; because they're shorter they will be easier to hold in place.
The front and back panels should be attached also on top of the bottom panel, but you want the side panels to fit sandwiched in between the front and back panels, not the other way around.
I used 1/4 inch untempered glass; cut it exact and then grind down the edges to make it smooth.
Make sure to account for the space the silicone takes up, however miniscule it is.
Any silicone will work, but I used DAP Aquarium Silicone, as it's 100% silicone and nontoxic.
Always get non-toxic aquarium safe silicone.
USE CLAMPS! Duct tape also works, but you'd need assistance to hold and tape.
Work deliberately and slowly, don't force the glass into place, move it gently into place. If you force the glass and clamp it down, the tension when you release the clamp or fill it with water could cause the tank to come undone.
A final afterthought, don't ever move the panels after you've let the silicone begin curing. If you do, you might as well remove the entire panel and redo it, because you'll get a leak guaranteed.
Last edited by AVN; 10-13-2012 at 10:53 PM.