Today there are a thousand biblical things to think about, you can spend many hundreds of hours on them but will not further your preparation for the return of Jesus. You must decide very carefully which will further your relationship with Jesus.
Remember, you must know Jesus personally, intimately, He must be the only One in your life you fully and completely trust with all your heart. You must trust Him with your very life. You must confide all things in your life to Him and know He will do the best thing for you.
This is knowing Jesus and He will recognize you as old friends when He returns.
It is so highly recommended you read the precious book The Desire of Ages written through inspiration by Ellen G. White. It is the foremost writing that details the life of Jesus completely.
Many book stores carry it, you can read it or buy it online. So highly recommended you get a hardcopy because there’s a possibility print may become scarce in the near future. That goes for the bible too.