How success can be achieved and failure avoided in international marketing?

By having local marketers with local experience spread worldwide and are in charge of the right implementation of your marketing strategy. A specific strategy isn’t always appropriate for all countries. Thus those marketers will be able to adjust the marketing messages, the tactics and policies of your (same) marketing strategy to fit better in their (different) environments. Those professional specialists should be ready to resolve tough problems based on cultural, social, technological and other differences among those nations (e.g. You may want to be the leader of technological innovation bringing the last cutting-edge gadgets in global markets first. Bear in mind though that this policy may fail in countries with low income per capital due to the fact that those gadgets’s start price will be high enough to practically prohibit people for buying your products. Marketers in those markets should implement your strategic positioning of innovator but should import the product of yours that are not the very last cutting-edge technology. They may wait for a short period for the product to be a little bit more cheaper or they can follow a different pricing policy in that country).

know ALOT about marketing and traps you can fall into
know languages well
have good character
i guess...