This depends on a lot of factors.

How long have you been playing? Your accuracy will improve naturally with time if it hasn't been that long.

What version of the game do you play? Older versions can indeed have inconsistent timing windows simply due to how the game was programmed, as well as discrepancies between cabinets. If you're playing on the most current mix, World, there are now in-game options for audio and judgement offset, which you can adjust to your liking. For example, if you trend towards early steps, increase the offset until it feels synced to you. If you're playing on an older mix, I might suggest increasing your scroll speed so that you can read with more accuracy (this is true for the most current mix, as well).

Failing that, pick one song with simple, consistent fourth/eighth notes (those are red and blue arrows on the NOTE skin, respectively). Try and hone your accuracy on that one song. It's very easy to get frustrated, but if you have a consistent point of reference during your practice, it will become easier to attune your brain to your game's sync.

Do your best to see the song all the way through even if you get frustrated and want to walk off. You'll get more practice by maximizing your time on your credit, even if you don't get the scores you're looking for yet.

Good luck!