One of the thing that can be success full at funding short film is product placement.
The following are the step by step on short film product placement.
1- Identified approx how many viewers the film will reach. The key for this number is research.
Check out how many film festival accept short film and their average festival assistance,
you can find this information on their web-site or calling the film festival coordinators.
2- Mark your Script. go trought each page of your script and mark in every scene the diferent products.
example: if there is a conversation in a bar. you know for fact there are products on the shelf, sigh on the walls and probably there is someone smoking at the scene, all this are potential buyers.
3. create a business presentation, remember with the info of your research you can develop a professional looking plan . the investors want to know how many people are going to be reached for their money.
4- Stay local, since is a short film. most of the big companies have representative on their areas. probably you even know them. do your research most of the time it only takes to talk with the owner of a bar to know all the promotion agents in the area.
Remember research and create contracts for product placemen, this will help you in case any future allegation, there are lots of legal templates out there you can use.