Tap with the keyboard instead of mouse buttons.
Dim your background 100%.
Disable the storyboard.
Get used to alternating between two buttons as soon as possible.
Get a clean skin that shows some transparency and/or just doesn't distract too much.
Pay attention to the approach circles because they help a lot, but don't focus on them too hard either, they are a tool.
Try to find the rhythm of the map, and let it guide you a little instead of relying too much on your reading ability. I read enough to know if the next circles will be on the beat or if they will be half beats, but I don't read enough to see exactly when I need to click the half beats, because I assume the timing by the music.
And when they say play everything, it includes lower and higher star ratings too.
And play a LOT of different maps because star rating is far from a perfect indicator of difficulty.
But don't waste your time with maps that are so hard that you just flail your mouse and try to catch the circles, that's pointless.
And an advice for later when you will be playing 4* maps, gradually increase your mouse sensitivity. Keep making it slightly too high for comfort and you will get used to it, and then raise it again a little too much for comfort again. I use a basic cheap mouse and my sensitivity is 1.85 and that's enough for the maps that I play. I have increased my sensitivity by jumps of 0.5 or 0.7, at least 5 times, probably more.
It's only important when you start playing maps where there are too many things going on in different areas of the map and need to go be quick, or when a map has long distance jumps.
I'm a survivalist like you, I like to play maps that are hard or too hard for me. Thanks to that, when I play in multiplayer, I usually get ahead during difficult or complex parts, but I usually get behind if the map is too simple because I get stupid misses and they don't. I should practice lower star rating maps more, and you should keep that in mind... But I suggest that you keep pushing yourself the way you are doing, because 4 star maps are really the best place to be. The maps are usually of higher quality, they are more fun, and there are plenty of them.