Step 2, ocean currents
So now you have a base map, you will add a bunch of layers on top of it... a lot. So get yourself onto a "layers" drawing program (in other words, Paint won't do).
Time to find the "logical" ocean currents. Now, this is pretty easy and I'll trace it in a few steps.
1. Close to the equator there are two currents, flowing westwards. These are the strongest and the first to be drawn. In between them two (most of the time, exactly on the equator) is a counter current flowing eastward - Draw these currents in black. As the currents are more or less parallel to a latitude line, there isn't a significant exchange of heat between the water and the surroundings.
2. As these two strong currents meet a continental basin (not necessarily the shore, see last post) they get diverged away from the equator (northern one will move north, southern one will move south). They will stick to the eastern border of that continent approximately until somewhere between 30º and 45º of latitude. During this time, they release heat brought from the equator and are, hence, warm currents - you should draw them in red.
3. At the 45º West -> East winds (the westerlies) are blowing strongly enough to create an eastward current. However, this is no sudden right angle turn, it actually starts much sooner. The warm current you drew is no longer as warm, is now moving in a more or less stable latitude and will not exchange heat - draw in black.
4. As soon as this current meets continental shores, it spreads north and south (and wikipedia says it sticks pretty glued to the coast both because of the properties of the colder water and because the westerlies don't blow offshore at these latitudes on the western coasts). The currents moving back to equator will take reasonably cold water, which removes heat from the air in the region they pass through - draw them blue. The part that flows north takes relatively warm water to the poles - draw in red.
5. All it's missing is the circulation at the poles. It isn't clear in my map because the continent is mainly tropical/equatorial and it wasn't needed. All you need to do, if you have polar oceans/seas, is to close the loops, keeping the color code for currents moving poleward (red), "equator-ward" (blue) and laterally (black). Remember, unless you close every loop, you are saying water piles up somewhere, and if you are saying that, you are wrong.
On the map there are a few currents which have been placed to close the existing loops. Kuy and Santellan currents are the feeding currents for the Northern Equatorial. Since the latter needs to exist the loops needed to exist and to be closed. The Kuy current is also forced to exist as the path eastward is blocked by the warm Palamb current that is moving north and partially blocking the West-East surface movement.
The Hondan Southward current is generated following the same logic as before. Warm water flows south/southwest from the equator in every continental shore facing east in the southern hemisphere. This generates the said current. To close that loop there's the Ohamana cold current.
EDIT - noted a couple of errors in the instructions for the temperate westward currents, I think it's better explained now and error-free.
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