Reply to some questions from a newbie

Hi guys,

I am still quite new in DJing world and no doubt still practicing beat matching all the day. Since I know nobody who does also DJing, this would be the best place for me to ask questions. I have tried to find some answers but unfortunately nothing. So here are my questions:

1. when im doing beat matching, it happens very often that everything sounds well, but then when i drop in the next song, there is a very little difference between two songs and it's audible. do i need to listen to the two songs at the same time in my headphone?

2. sometimes the overlap of two songs get very long, i mean more than 128 beats. And the two songs have still tiny difference bpm and therefore after so-long overlap, they will be out of sync. and i found it's difficult to tell which one goes faster until the difference got bigger, but as the first question when there's only a bit difference it would be audible, but i have totally no idea how i can fix it.

I know i still have to put more effort on it, but im just wondering if there's some solutions for these problems besides practicing to death any suggestion is welcome and thx in advance!!