A friend and I went on an 8 day trip to Bali in November, 2015 and trust me when I say this, the island is full of surprises and adventures. I'm here to share some of my experiences through things I did right or wrong for every person to make the most out of their trip to Bali.
1) Credit Cards and/or ATM Withdrawals vs Money Exchange
One important thing I learned was that it's cheaper to use a credit card and withdraw cash from at ATM for places where they wouldn't accept cards. Now my credit card doesn't charge me any extra money for using it out of India, simply applies the exchange rate applicable at the time of the transaction, so I got an exchange rate of around 195 IDR to 205 IDR per INR. My ATM card also provided me the same exchange rate but charged a further 250 INR per withdrawal, which in retrospect wasn't too much. In comparison, the official money exchange centres were offering 169 IDR to 176 IDR during the same period. Further, it's rather safe to withdraw smaller amounts from an ATM as and when required than getting a larger amount from the money exchange. (Converting INR to USD from India and then converting USD to IDR in Bali saves more money if money exchange is your way to go)
2) Buy Alcohol from Indian or Singaporean/Malaysian Duty Free
Alcohol in Bali is not expensive, but its not cheap either. The problem though is, that the hard liquor served at night clubs is atrociously diluted. Having said that, if you like to have a couple of good ones in your room before you leave for a night of partying, one can't buy a bottle of hard liquor off the shelf in Bali. There are a few illegal shops, but then again, dilution is a problem. Now, Bali Duty Free is quite expensive than any Indian Duty Free and if you're flying through Singapore or Malaysia, it's even cheaper there.
3) Fly by Tiger Air or AirAsia
Tiger Air has a halt at Changi, which, trust me is the best airport ever. One can never get bored here, it has got wonderful theme rooms, a movie theatre and even a playstation section. The better part, all of it is free. AirAsia halts at Kuala Lumpur but both of these airlines are cheap and completely reliable and that only means having more money to spend at Bali. P.S. Just remember to fill drinking water after security because they won't serve anything for free.
4) Stay at a Hostel
If you find the right hostel, it can easily elevate your overall experience. Staying at a hostel is cheap and one can find many other like minded people to socialise and have fun with.
5) Gili T
When in Bali, one should really consider going to Gili T. Now the number of days you spend here completely depends on your total duration in Bali but I'd definitely recommend staying for at least two night. The island, where no motored vehicles are allowed, is one of the best escape spots I've ever seen. The clear blue waters, the occasional dolphin spotting, the bike rides on the beach, the crazy night parties, the amazing beach restaurants, the night food market, the snorkeling with the fishermen or the Jiggy's Boat Party all of these are so amazing, I really don't know how to rank them. Well to sum it up, I'd say, this is a must visit but one must remember to pack light as you may have to carry your luggage for quite a distance as the horse carts are a little over priced.
6) If you haven't ever Scuba Dived, this is the place to begin
Bali and the adjoining Gili Islands are filled with beautiful diving spots and some of them are even the best rated in the world. It's cheap, it's easy to find and thus this is absolutely the perfect place to try diving for the first time. And it's something that everyone needs to do at least once in their life. One dive completely changed me, so much so that, I went for another one and my fascination for the underworld world has grown so much that I'm going to get my Open Water Diving Certification soon and hope to be a Master Diver some day. Obviously, it doesn't work the same way for everyone, but, my friend who also dived for the first time does absolutely agree that it was one of the most beautiful and mesmerising moments of his life. One might want to skip doing it at Nusa Dua though, it's over commercialised.
7) Kuta Legian
One would read all about the Kuta Legian street being the most happening place at night in Bali. It actually is if one intends to score a new one night stand every night, but there is nothing more to it. If you'd rather explore other places, my advice would be to not spend more than two nights here. The place has no more than 6-8 good night clubs, all of which can be covered in one night alone if wanted.
Having complained about Kuta, this is my alternative. After two nights in Kuta we ended up travelling to Seminyak all of the other nights for it's swanky clubs, exotic restaurants and, in general, better experiences. Shopping can be a little more expensive here but one can always go to Kuta for that. To conclude, one is better off staying in one of the hotels here for a longer trip.
9) Ayana's Rock Bar, Potato Head Club, Ku De Ta & others
There are tons of sea facing high end clubs in Bali that one would read about on the internet. All the reviews seem pretty awesome and so are the places. The only problem is, if you've seen one, you've seen all of them. Not taking any credit out off any of these places, they all have great food, great ambience, great service but are all expensive and they all look the same. If you're on a short trip to Bali, one of them is a must go to place but, don't bother spending your time and money trying to cover all.
If you ask any local in Bali where to find the best seafood, they'll immediately recommend the long line of sea facing shacks at Jimbaran but these restaurants have been doing the same thing since the beginning and the meals they serve are hardly close to splendid. Jimbaran can be excluded from one's bucket list and there are tons of other good seafood restaurants on Zomato.