I've looked at photos taken with various lenses and 50mm 1.8f seem to give the kind of photo that I want.
On a crop camera or on a full-frame camera? The A6000 is a crop camera and 50mm on crop corresponds to 75-80mm on full frame: in the case of Sony, it corresponds to 77mm. 50mm on full frame corresponds to about 33mm on crop in the case of Sony.
So, if you have seen 50mm crop photos, all is well: just buy the 50mm lens. But if you have seen 50mm full frame photos, you should be looking at a ~33mm lens for your crop camera.
For macro photography, too short lenses can mean your working distance is so small that you could annoy the object (if photographing insects) or at least block the light.
Too long lenses can mean the small aperture needed for useful depth of field requires a long exposure time, so long that you can shake the camera, which is magnified by a long lens. Here, image stabilization can help. However, not all image stabilizers stabilize the camera displacement: they may only stabilize camera rotation. At long distances, camera displacement has no effect and only camera rotation matters in camera shake, but at short distances, both are important.
I would be looking at these features:
- Maximum magnification -- note that your camera has a 1.53x crop so this doesn't matter so much as it does with full frame because the sensor is already effectively magnifying by 1.53x when compared to a full frame sensor
- Focal length
- Working distance (depends on focal length and magnification)
- Good image stabilization (IBIS can be enough, too) -- try to find out if it's stabilizing only camera rotation or also camera displacement
- Quality of autofocus system, including focus limiter if you feel you need it (although a camera may have a setting to not aimlessly hunt for focus when it doesn't know which direction to adjust the focus, which may be enough for you)
- Usefulness as a general purpose lens -- the more uses a lens has, the more likely you have it with you when you happen to need a macro lens
- If the lens is very long and heavy, tripod mount
- Size, weight, price, etc. -- all the usual features you're considering when purchasing a lens