Watch the alcohol level. See through the alcohol to the person and go for the real person. Know your sexual limits beforehand. If love is your objective, save the sex for later. Build the romance and emotional tension instead.
Vacations can be both, but there is no doubt that they are good for a fling.
Also remember that vacation romances need not turn into long-distance romances. Select vacations close to home or where people from your area tend to go. Weekend retreats are good examples. Another thing you can do is go with someone you already like, respect and find attractive on a vacation together as a couple or in a small group. That way you can hook-up with someone you can land more easily.