For starters, rather than merely guessing how something animates, it is much more useful to reference and study the subject at hand. What your mind assumes to be correct may be missing when if comes down to actually animating. The human eye can and will detect faults as it understands how something moves.
Let us consider the following when it comes to reference:
Shape/size/weight: It is important to know how heavy an object is as it animates, as a bowling ball on a rope will have more weight than say a tennis ball on a string. Knowing the weight of an object will allow you to judge how fast the object moves, how much time it has to get to a new position and how quickly it can start and stop.
Timing: Timing is key to believability as something that moves too fast or too slow can make an animation seem out of place. Blocking out the time objects move from pose to pose will allow you to get a feeling of how the frames in between will move and where they should be. Knowing how many frames it will take for an object to go from position A to B is important to ensure the objects mass and shape fit.
Blocking a star jump
Animation: Finally, understanding key rules of animation such as overlapping, squash and stretch (where necessary) , slow ins and outs, anticipation etc will add to the overall appeal of the animation. Sometimes the character being animated can have all their personality in just their animations alone, without the need for facial expression or even speech. A great lumbering animation will show a character of strength whereas a quick snappy animation can show speed and cunning.
Being able to draw is not 100% necessary in the blocking stages as long as the movement is shown clearly, though for more detailed animation with expression, exaggeration and minor details it certainly helps.
Animation test for Disney's Tarzan
Using references, understanding and researching the material and blocking out animation before diving right into the the final cut is key to ensuring the animation will be successful.