One of the keys to attractive, usable layouts is keeping things neat and orderly. You should make a point of consistently sizing and aligning your fields, text, and other layout objects. One way FIleMaker Pro attempts to help you be a brilliant interface designer is by using Object Grids, a feature that "snaps" layout objects to the nearest point on an invisible grid. Object Grids is toggled from the Arrange menu (visible only in Layout Mode). Helpful as it may be, however, Object Grids is a blunt instrument. When you need fine control over the placement of your layout objects, it's time to turn off Object Grids and start using alignment tools.

Figure 1: Alignment feng shui -- Do "center" and "middle" really have different meanings?

Figure 2: Alignment part 1 -- Observe how the widest object in the group becomes the anchor for all the objects. All the smaller objects move to the center line of the largest.

Figure 3: Alignment part 2 -- In this scenario, not all the objects are in the boundaries of the largest (heavy dashed lines). When aligned, FileMaker Pro moves all the objects to the center of their combined width (dotted line).
The six basic alignment commands shown in figure 1 work as you might expect them to. Select a few objects on a layout, choose Align > Left Edges and the objects line up to the left. Simple enough, but how does FileMaker Pro "decide" where that left edge starts? When aligning objects to the left, FileMaker Pro chooses the object with the edge furthest to the left. The same goes for aligning to the top, right, and bottom. Middles and centers align a bit differently. When aligning centers, if one object you're aligning is wider than the others and the others fit in the horizontal space of the largest object, all other objects will align with the center of the largest object. In all other scenarios, the objects will align to the center of their total horizontal space. Aligning middles works the same way, but in vertical space rather than horizontal. Refer to figures 2 and 3 to see this concept illustrated.
My favorite alignment tip is for aligning field labels above their fields. Often, when working with list layouts, I make several changes to field widths so each column is just as wide as it has to be. Changing a field's width can throw off the placement of its label that I once had neatly aligned with the left or right edge of the field. When I have a field label that lies to the left of the field I just painstakingly resized, selecting them both and aligning the left edges will cause the field to jump to the left and out of position. There are a few ways to get these two objects lined up the way I want, but the quickest by far is to select them, align right edges, then immediately align left edges. Just two keystrokes get it done. By aligning the right edges first, you move the field label's left edge past the left edge of the field. Then when you align left, the field is the leftmost of the two objects and the field label is moved into alignment.