The superstructure of the Buchanan kit has a number of butt joints. There may also be some miter joints, though you seel them more on Trumpeter kits. The key is preparation. Dry-fit the parts. True up the joints with a quick pass with a fine sanding stick (not too heavy - don't want to reshape it). Then cement together with liquid glue. Apply the glue to both pieces & allow them to soften for a few seconds - then squish them together - allowing a fine bead of softened plastic to ooze out of the joint. Once the bead is hardened it can be knocked off with a Xacto knife or sanding stick.
More prominant joints can be filled with CA, hit with a shot of accelerator, then sanded right away. Another good solution for larger seams is good old white glue (ie Elmer's glue). Add just enough to slightly overfill the seam - it shrinks as it dries.
The key is to work in assemblies, dry fit, & correct/adjust the fit before committing to glue