Definitely a good idea to get a year or two teaching under your belt in your home country first, but some people get jobs straight out of teachers college or uni, just depends.
Then you have a couple of options to get overseas jobs.
Times Education Supplement (and their online presence) advertise very heavily for teachers all over the world. I’ve not been successful using them, but gives you an idea and I’ve heard a few people have got jobs that way.
Most of the biggest schools and best jobs are obtained through 3 or 4 teacher recruitment agencies, they cost, but it’s worth it. Some people try applying directly to schools, but the big schools won’t waste their time, and the smaller schools have smaller reputations and salary packages.
Generally, you are better off, and advised to not limit yourself to just a single country, but to cast your net wider, there are many good schools and jobs all over Asia, the world in fact. Consider each on their own merits.
The Recruitment agencies I recommend are;
They will check your references and qualifications (as well as answer more questions) then you are eligible to attend a recruitment fair, sometimes in Jan or Feb. (essentially 100 schools world wide send principals and about 200 or 300 hopeful teachers attend a hotel in London, Malaysia, Bangkok, USA, or Australia for 3 days and make as many interviews with each other as possible.
If you are a decent teacher you will get 2 or 3 firm job offers there and then, some will contact you later, and there are more fairs in may or April. most international schools start in August.
It is usual to sign a 2 year contract to start with.
Salaries vary a lot, but so does cost of living, so take that into account. ($20,000-$80,000 per year) also most will pay flights per year, health insurance, end of contract bonus (typically 10% of gross salary), shipping of your goods, provide or pay for housing etc.
If you are determined to get a job in a particular country, eg Indonesia, check the local English language newspapers, the Jakarta Post or the Jakarta Globe etc for jobs advertised, but stay on the books with at least one agency, in case a teacher suddenly leaves etc, they may call you. BUT do not be in country when you go for an interview, or you will be awarded ‘local hire expat salary’ which is still good. but if you are interviewed outside of the country you will be considered overseas hire!
Depending on the school (and remember there is not law or copyright on the word international school or American school, so ANYONE can start a two bit sweat shop and call it the John Doe International School of Excellence ) so DO YOUR HOMEWORK before signing a contract.
In terms of qualifications, they usually want a teaching degree of some sort, several years of experience in your home country and further qualifications such as a Masters degree certainly does not go astray. Make sure you have all your references ready and up to date.
Search Associates requires a couple of parent references too, so make an effort to cultivate a few parental relationships early in your teaching career, chat to some parents, visit basketball games, go the the school play and be sure to congratulate the parents afterwards on their children’s efforts. Then when you need to ask for a reference you will find many of them more than happy to do so.