The best way to get a good bargain in property purchase could be if you can find a few like-minded buyers and form a group which can then go and negotiate for a bulk purchase. This can help you extract a good discount. So when you decide to buy a property, make sure you visit the site and try and make that visit on a weekly holiday so that you can meet some more prospective customer. Interact with people and float the idea of forming a group for bulk purchase. Most genuine buyers would be too happy to be part of it and it is not very difficult to find a few like-minded buyers.
Secondly, if you have the ability to pay a larger amount of money upfront, you have an extra bargaining power. Same applies to buyers who would be going for one-time payment in the case of an under-construction house. Builders and realty developers are constantly in need of funds to invest in upcoming projects. So they would be more than happy to offer you a bigger discount in such a case, though it may not be financially prudent to pay the entire amount at one go for an under-construction house.
Thirdly, if you can obtain a pre-approved loan from a home finance company of bank for a home loan, based on your income, it would help. Because that would convince the developer that you are a genuine buyer and would also show that the deal will materialize quickly if they allow a little concession. A loan pre-approval will show the developer that you are serious. Let him know that you are pre-qualified for the amount you are offering
If sales volumes have dropped and there are many unsold apartments in the vicinity, point this out to the developer and use the fact to your advantage. An unsold apartment will cost the developer more over time than lowering the price and selling the unit quickly
If the market prices of the property have fallen and there are several unsold units, it may be possible for you to even bargain for a larger discount.