Beat matching is maths, plain and simple. You need to work out the percentile of the pitch speed difference between the two.
For example, I know the tune I start my sets of with currently is 170bpm. I like to play my sets around 175pm (it's a comfortable speed for me), so I set my pitch to 3% on the deck with the 170bpm tune on it (3% of 170 is 5.1, so the tune is now roughly at 175pm). The next tune I want to mix into it is at 172bpm, so I need to get that tune up to the speed of 175bpm so it is matched with the other deck. I know instantly that the pitch increase needs to be around 1.7/1.8%. Why? 2% of 172bpm is 3.44. So if I have my pitch set to 2% on the second tune, it will be running ever so slightly faster than my first tune (at 175.44bpm vs 175bpm), so it needs to be slightly slower than 2%. Probably closer to 1.8%. Voila, the two tunes should be beat matched.
A basic knowledge of maths and knowing the bpm of your tunes is MASSIVE help to beginners. The fine tuning, now that comes with time and progress. Knowing your records is the same as knowing the bpm of a track. In time you should be able to work out the bpm of a track just by listening to it.
Over complicating things to be honest.
1.Listen to track 1
2. Cue up track 2 on the headphones
3. Use the pitch to get the track in time
Hey presto! I've just beatmatched without using maths or a BPM counter!