This is my first attempt at a fully movable object that requires no assembly after printing. It is a fish skeleton that articulates both horizontally and vertically thanks to the joins that connect the rib bones to one another.
A higher resolution ensures that the joints are smoother, so a medium to high resolution would be preferable.
Generally a high infill keeps the joints on the model strong, so they are less likely to break.
In order to make sure some moving parts do not combine with other nearby objects, decreasing the initial layer thickness can help the first couple cross sections separated. This can affect how the object sticks to the printer bed, so be sure not to decrease this too much. The first print of this object came out perfect with an initial layer thickness of around 110%. On another note, the fish in the above image was printed without rafts, so they may be added, but cleaning them up may be more trouble than they're worth.
Note: Be sure to orient the fish onto its side before printing, otherwise I'm sure that it will spaghetti.