I need help

My issue is playstyle I try and play safe after lvl2 passes until I get my items but I see perfect opportunities to get kills and they are missed by like 20-10 hp but they back so I stay in lane ( 3/4 or 1/2 hp ) and when they come back I die Then I miss vs cause I tp bot ( or roam if I take exhaust or ignite ) and the same thing happens they get away by 10-20 hp if I dive I get kited so I let it go But now my lamer has more cs and more hp so I end up dying and the cycle continues How do I set my mind to only playing safe and farming or how do I make sure I get kills

And how do I play when ahead by 15ish ( or more ) cs and 1-4 kills

Bonus : how do I practice my auto attacking between spells and other auto related mechanics ( what should I set up in practice tool or custom game )

Thank you soo much if you take the time to answer me