Are you using the right adhesives to bond materials together?
While you can glue most anything together with superglue (who hasn’t glued their own fingers together at one time or another?), some materials just won’t stick. It gets really confusing when you start mixing different materials. With this handy adhesives chart, you’ll know if glass can stick to ceramic, or if cork will bond to plastic, and much more variety of materials to get the best possible results.
Update 6/1/2016: DAP Products just came out with a CA glue, Rapid Fuse, that bonds most anything and has a fast cure time of 30 minutes. There’s also an adhesive version for wood. I tried the wood version and it works very well, read my review here.