Assuming the map is complete (ie. covers the entire planet from pole to pole) and uses a sensible projection, you can find the equator and poles geometrically: the edges that match up are east-west, the poles are the other two edges, and the equator runs down the middle between the polar edges. If the map isn't complete (it doesn't run to the poles, or it doesn't circle the entire planet), you can't determine the poles or equator.
You can find coastal mountain ranges and coastal plains: a "ragged" coast like that of Norway has a mountain range, while a smoother coast like that of China is evidence of a plain built up by river deposits.
If large lakes/inland seas are marked and you can tell north-south from east-west, you can identify a recent ice age by abundant lakes in the northern and southern land areas.
If the map is detailed enough, you can spot river deltas even in the absence of marked rivers; these are good places to look for civilization.
You can deduce plate tectonics and mid-ocean ridges from the shape of the continents; you may be able to deduce rift valleys and uplift mountains as well. From this you can figure out various things, eg. that Iceland is volcanic.
If you know where the equator is, you can figure out the prevailing winds, and make broad deductions about the climate (eg. a coastal range with a sea-to-shore wind will produce a rain shadow desert and a rainy/foggy coast).