You are like adc, but with no range u have to let fight begin and jump in when opponents are at low hp, never initiate fight, never go in first, and never jump on full hp team.

Depends if u get all blue's dont buy tear of the godness/manamune. If u are roaming hard buy boots of mobility if u get poked hard buy green boots, or mercury's treads. If opponents have strong poke buy warmogs, if they have strong DPS buy GA (if u didnt buy manamune buy both of them).