Sounds like you are moving in the right direction. Here is some more info for you. Not sure how much of this you already know, but I figured I'd post just in case. Good luck.
P0102 OBD-II Trouble Code
Mass Air Flow (MAF) Circuit Low Input
This means that there is a problem with the Mass Air Flow (MAF) sensor or circuit. A more technical description would be that the MAF circuit had lower than expected voltage (air flow).
You will likely not notice any serious drivability problems, although there may be symptoms such as a general decrease in power or sluggishness.
A code P0102 may mean that one or more of the following has happened:
The MAF may be disconnected, or a wiring connection may be bad
The MAF may be dirty or otherwise contaminated (Note: if you use a reusable oiled air filter, be careful not to apply too much oil or that can contaminate the MAF).
The MAF sensor may be faulty
The vehicle computer may be faulty (very rare)
The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures:
Verify that the Mass Air Flow Sensor wiring is connected properly and that there are no broken / frayed wires.
Inspect for any air leaks near the MAF sensor.
Take the MAF out and clean it using a spray cleaner such as brake cleaner or electrical contact cleaner. Be gentle with the sensor.
Check the voltage of the MAF sensor (refer to a repair manual for vehicle specific information)
Replace the MAF sensor.
P0300 Code - Cylinder Misfire
Random/Multiple Cylinder Misfire Detected
A P0300 OBD code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.
Symptoms may include:
the engine may be harder to start
the engine may stumble / stumble, and/or hesitate
other symptoms may also be present
A code P0300 may mean that one or more of the following has happened:
Faulty spark plugs or wires
Faulty coil (pack)
Faulty oxygen sensor(s)
Faulty fuel injector(s)
Burned exhaust valve
Faulty catalytic converter(s)
Stuck/blocked EGR valve / passages
Faulty camshaft position sensor
Defective computer
If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.
If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell an odor resembling rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.
Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.