I may be wrong. Someone correct me if I am. I've heard that putting ice on your scrotum works because since the scrotum is depleted of sperm then colder temperatures help them produce sperm faster. The faster they cool down then the faster you can get back to business.
I think it is very difficult to influence the time period which is needed before having a new erection. It also varies due to age and individual characteristics. In general, I would say that the younger you are, the easier it is and also the longer you was without sex, the easier it is, too. I remember that when I had not had any sex for longer periods, I could have new erections very soon after ejaculation, but on the other hand there was also a danger of premature ejaculation (especially with the first ejaculation).
Then, it may also depend on the form of stimulation - if you try something new after the first ejaculation, there is a higher probability that a new erection will occur - in the most extreme cases I´d say that a new partner after the first ejaculation will guarantee a new erection as well - I have never tried it this way though, but there are some documented studies on this (also in zoology). So, I would say, try something new which you did not do during the first intercourse, new situation, new forms of stimulation etc.
Also, I guess that if you have something like "weaker" or "slower" orgasm, you can recover faster. For example, if you start to have orgasm, you let ejaculation happen without any intense stimulation (or if the first ejaculation starts, you can stop moving, let it happen and probably the time needed for recovery will be shorter).
However, these are just my personal ideas and observations, so it may be different for different people.