Easiest first bud.

Check for spark. Well obviously you will have spark since your car starts, but the strength.
Move on from that and check your plugs.
Water contaminated plugs causes hesitation at certain revs (dont ever wash down your engine.) Along with fouled plugs (start and stop without the car warming up)
Then to go abit more technical you can check the resistance in the leads.

If all your electricals/ignition side is ok, start pointing fingers to mechanical.
80-90% of the time, a rough engine is due to an electrical problem.


Im not saying youre not well educated but saves you from asking, so here u go :

Check for spark. Take a lead off. Take a decent length screw driver. Stick it up the lead until it touches the metal piece. Place the exposed metal bit of the screwdriver close to the rocker cover. With the help of someone else, crank the engine and inspect the spark.

Take the plugs out, well you just need a socket with that lol.

Resistance in the lead.
Take one lead out at a time (so you dont mess up your ignition timing) Get an ohmmeter or multimeter with ohm function, place a terminal on either end of the lead, and measure the resistance. Im un sure of the specs, but different leads have different specs.

Sometimes fixing a problem doesnt mean you need to replace a part. =]