The correct joining procedure is the one stated in the airfield information which is usually a standard overhead join because that is the only one that is published.
I noticed a few posts saying that some join further up
The crosswind join is perhaps the worst choice as you are crossing any departing traffic without the benefit of having the opportunity to look down and observe the airfield from above. To join further up gives you even less chance of observing the airfield and nobody else has a clue what you are doing. All to often you hear an aircraft report overhead or deadside descending and yet there is no aircraft anywhere near the overhead. It is important to make the right calls in the right place so that other people know where you are, and you have good view of the airfield and any traffic. It is also a legal requirement to report entering and leaving the ATZ; how many do that?