I'm preparing for JEE, I'm having very low score like 40 to 50 in mocks but I'm not giving up so I'm thinking about focusing on April attempt to score 99 percentile I have boards it is good idea ? Meanwhile I will prep for advance too just guide me how can I reach there

Hello dear aspirant, as you mentioned you are getting low scores like 40-50 then don't get demotivated because of these scores just continue to put in all the hardwork and all your efforts for the  january attempt itself so you'll be fully prepared enough for the april attempt . Try targeting the january attempt with all the theory you have learnt till now and try solving pyqs based on them and also try to complete rest of the theory part since you'll have your boards too. When you're giving mocks just try to recall all the  theory you have learnt and once the test is over analyse it properly and try to find out your weak topics and revise all the topics you have made mistakes in and write down them in a separate notebook. For the january attempt just complete the rest of the theory by one shots and give one mock everyday and analyse it daily without fail. Once the january session will be completed by then you'll have completed all the theory part so for the second attempt and you'll have two months to go through question solving and rest of the pyqs . Just be consistent in this process...

Thank you and ALL THE BEST !!!