How can I prepare for iit jee by self study ?.....I am in 11th class.

Preparing for jee is a tough task , so, by self study you can clear mains but advanced u need a bit guidance , so, do 1 thing . 
just go with right study material , and do 250+ ques of each chapter and take test series of resonance or allen . 
and if u are intrested in online then take self study package of askiitians , that will be benificial . 
HOPE IT CLEARS 
regards