The easiest way is to use a miter saw to cut the ends to square. Clamp the ends together while you drill the pocket holes (preferably with a jig). Also never screw into endgrain so make sure you're putting the pockets in the correct orientation. If each corner is square then the entire stand should be square. It's more important to keep the side that contacts the aquarium bottom to be flush all around than for the holder to be perfectly square though.
Do you mean to use a miter saw to cut a block or something to use as a guide? I have a miter saw (only saw I really have) but it's only big enough for cutting smaller pieces. I believethe blade is about 7 inches. Can you explain more about the engrain? Having a hard time visualizing.
Now that I think about it, there are 4 ways to put in a pocket screw for each edge or corner..like this: https://ibb.co/i35N0G
...is this what you're talking about?
I discovered hardwood veneer tape, which can be applied to the edge of the plywood. I think its the same idea except you are actually cutting the strips.
I caution you to not "bite off more than you can chew." I made this mistake, started watching woodworking videos, built a table saw, all so that I can build a marginally better looking stand.
My advice is to stick to your design. To connect the plywood, use pocket screws. There is a tool that allows the screws to be drilled and inserted at an angle. With 3/4" plywood, you can do this from the inside without seeing any external screws. For the plywood edges, get some veneer tape which you apply to the edges. It hides the plywood and makes it look like hardwood. Or, you can get some edge trim to hide the joints and plywood ends.
Another strategy is to keep it simple. make it strong (screw and glue) then paint it black to hide the imperfections. Is this something for the basement, or is it in a finished area?
Yea I'm trying to keep it simple since I know that i don't have the skillss. A box with a few shelves is ismple right? The biggest concerns are figuring out how to join them properly to make sure enough strength. My plan right now is to make a box with the front open, 2 vertical panels to hold the middle and include a few shelves. I'm picking up a kreg jig for pocket holes and am just worried about keeping things square since I don't have a dedicated table for doing this kind of work.
Any advice about which back plan to use or about what direction to put in the pocket holes (https://ibb.co/i35N0G)?
Also, it's for the living room
want to be considerate with my wife. she is all for having tanks so I want to at least keep the house looking nice. If I was by myself, I would just do cinder blocks
pretty furniture + pretty tank = more future tanks