A few factors that I try to keep in mind are;
-Is their adequate flow? Enough for the coral to mature into.. but not too direct or one dimensional. I try to place most Acroporids where the polyps are getting rocked from side to side (what is commonly called 'varied flow').
-Spacing. Will this coral have room to expand/encrust without running into it's neighbor? Some species grow like weeds and will quickly take over slower growing ones. Others are more sensitive and require intense lighting/specific flow and will quickly decline if their requirements aren't met.
-Lighting. Am I providing enough light for this species? and secondly, will this coral shade others around it? Plating species need to be placed in areas where they can develop without excessively shading other corals. Some Acros can also block a significant amount of flow and light as they gain mass.
Just a few thoughts...