Why do you want to adjust it? Is it too hard or too soft? Good, now I have more to go on as far as your concern goes. On earlier years, there is a cable that has 2-> 12 mm nuts that can be loosened and then the tension on the cable can be tightened or loosened. On later Hondas, the throttle pressure is controlled by the computer. See if there is a cable from the trans that is pulled by the throttle being opened. If not, then you need to check for codes in the transmission. It could be a speed sensor not telling the computer the correct time/manner in which to shift the trans. Has any work or fluid changes been recently done to the trans. Do you have a Check Engine Light on?
I was about to ask the same question as Dan. Is it the pressure of the accelerator pedal. I have seen people try to adjust the idle speed by adjusting the screw at the throttle housing. Adjusting this screw which is set at the factory may result in the throttle butterfly jamming in the throttle housing when the engine cools down. When the driver starts the car from cold the accelerator pedal appears to jam or stick!
Honda ATF-Z1 is the recommended transmission fluid (it is not very expensive) for these transmissions but a lot of people wouldn't recognize the difference in shift characteristics the genuine fluid gives. It's probably too late for your transmission but driving the car until the oil in the transmission gets up to operating temperature, draining the oil, refilling with the genuine transmission oil and perhaps adding an oil additive called Lubegaurd (its a friction modifier) may get some extra life out of your transmission if is not past the point of no return. The transmission oil level is checked on level ground with the engine switched off after haven driven the car and engaging all gears.
This model does not have a throttle cable, it's controlled by the computer. There are sensors on the transmission that the computer reads and determines when to shift. If it shifts hard it could be from a sensor not reading correctly or not reading at all. A qualified technician with a scanner can isolate any sensors that aren't reading correctly.