Moving objects in one plane at a time

Greetings,
I am forever wanting to take an object, duplicate it and place it in a location. However the system thinks it knows better where I want something, which is almost never where I want it. I then try to use move to slide the object up, down, left or right. The Move tool unfortunately wants to slide the whole thing in any direction except just up, left or right.

 How do I restrict move to just one axis of motion at one time?  I am building a deck for reference and I want nice right angles and beams all in one plane, if that helps explain what I am doing.  
  Thank you in advance for any help.

Select the object, then “M”. Then hold the up arrow to lock onto the Z plane, the left arrow for the X, and the right arrow for the Y (those last two could be backwards, though).

Holding down the arrow keys will work great like TKizzy recommends, but you should also try “inferencing” which is SketchUp’s greatest strength. When you click M after selecting the object try moving the object in the same direction as the axis, you will see a dotted track from where you clicked the mouse to where you are moving it. This dotted line will turn green, red or blue when you “inference” those directions. Just look at the colored axis in the drawing to orient yourself. You can also snap to vertices when moving objects.

Thank you. I have been frustrated every time I use SketchUp because I had to waste time lining things up.

Yeah, this is going to certainly save a ton of time! Glad I could help!

Don’t “Hold Down” the arrows - just tap them once to set the inference line and tap again to un-set it.
For precision, start moving in the direction you want, then type in a value (don’t click or move the mouse anywhere: simply type in a dimension and hit [return].)
Same goes with moving objects - click once to set “from” point and click again to set “to”; no need to hold the mouse button while dragging.

You might also try r-clicking on the selection and see if you can “unglue” - this will let you move it away from the surface it is on.