Place the tool close to center (+- .010") being exactly on center is less important then many imply unless parting to 0.000 in X
Aside from parting to 0.000 I set tool height with a 1/16" reading ruler from the lathe ways, this has never failed me.
Choose an insert for the material that you are turning and the speed at which you need to produce the parts on time.
Turn the stock at the speeds recommended by the insert manufacturer. If they last increase it.
Feed at the rate suggested by the manufacturer. If they last increase it.
All inserts will have suggested SFM, DOC and feed rates printed on the packaging so start there and adjust either up or down.
If you are not turning the part fast enough or have a wobbly machine your results will tend to be poor, wick it up and have at it.