It's such a cliché - 'an experience that changed my life', but that's what it was :)
I came for two weeks originally, but loved it too much to leave. VP Bali was nice to let me extend my stay over and over and over again and only pay as if I'd known from the beginning what the duration would be. In the end, I did 9 weeks in Program Ubud and one in WG, so my feedback is mostly relevant for the Ubud program.
One great thing about my experience was timing: I came nearly at the beginning of the ubud program, so it was great to see it find shape and even impact some of the changes. The kids are just amazing, so willing to learn, obedient, never get bored and just open your heart. So don't be nervous about teaching, just get some ideas about what you could do before you leave - activities, games for different levels of English (Google it, ask friends, remember what you used to do in school etc).
There is a curriculum in place, there are lessons plans and suggestions filled in by the other volunteers so once you get here, just take time to read them and you'll know exactly where the kids are. After that, you can come up with games and fun stuff to review the material (it's very important to always review existing material, maybe even more than half the time of the lesson) and teach new things. You may find some of your ideas from home are useful for this or not. But I assure you, ideas will come. Just remember: make it fun and the more competitive, the better. The kids love that. Be prepared to have varied attendance, so adjut your lessons accordingly - cover the same material more than once, make sure everyone has learned a certain topic etc.
In program Ubud, they encourage co-teaching, which means you get to teach with an existing volunteer so that also helps to warm up and find ideas.
The highlight for me was the interaction with the kids: palpable progress leads to joy of teaching.
I'm happy to report no difficulties for me. The only bump in the road was not due to the place or the program, it was meeting people that do not seem to come for the right reason. That made me sad because these kids deserve everything. So make sure you come to give 100% percent to the cause, and not for fun or travel or any other reason. Of course, there is enough time to explore, but that can't be your priority. When you put the kids first, you get the most of the experience and if you're lucky enough after it, you will know your life has changed. And you will be surprised to hear everyone around you say how much you've changed also - who knew they can tell?!
Keep in mind local culture and habits: don't expect things to go on a roll, expect things to take time and plan accordingly, be proactive and organize anything you want to do, don't leave it to anyone else.
If you want to fund raise for the kids, that's a great idea. I did it after I arrived, but it is better done before so you have enough time. VP Bali can help you with ideas and logistics to use the money you raise (supplies, scholarships etc).
One small advice to make your life easier: try to get on local time. People in Bali sleep early and wake up early. You get the most of your time if you do the same - and this is coming from someone who could not get up before 10am or sleep before 12 am prior to Bali.
My daily activities included art classes (Ubud is great for that: painting, batik, cooking, pottery, you name it, it's there), spa, cycling, going out for dinner and jalan jalan - just walk around. There are many things to discover in Ubud.
In the weekends I did some trekking (Batur, Agung - this one is not for everyone, make sure you know what you are in for beforehand), visited the south of bali (Uluwatu and all the west coast there is great), went to Gili T and Nusa Lembongan (the diving is better than the Gilis and it's more quiet, so this was my kind of place. But if you like to party, Gili's is better).
Lastly, be prepared to be sad to leave, but don't spend too much time moping about it, or you'll miss the experience. You can be sad about it at home. And you can be pretty sure, the kids will remember you too. I've seen many volunteers come and go and the kids never forget anyone.
Thanks so much VP Bali. Till next time - I hope to come back soon ;)
Alex - Romania.