As a pilot who has just graduated, what are the ways to gain experience and flight hours?
The first thing airline look at is your flight hours, they usually require 1200 hours.
Is there any chance for a fresh graduated pilot to get hired in an airline with only 250 hours of flying?
I'm graduated in the Philippines.
There are a few ways to do it.
As has been mentioned many people here in the US are flight instructors (my instructor is building hours to go commercial eventually).
As has also been mentioned you could build hours taking trips with friends and splitting the cost but even split 3 or 4 ways this can get expensive fast.
You could do things like tow gliders or banners if they have that kind of advertising near you. It's not glorious and I can't imagine it's that fun as far as flying goes but it will build you hours.
I'm not sure how to get into flying planes for sky diving tours but that is another option to just build hours.
Again your hours may be an issue but you could look into ferrying planes for people. This can be tough if you don't have a lot of experience in different planes.
These are just a few things that come to mind. There may be varying laws in your area so its worth checking up on that before trying any of these things.
You can instruct or split time with friends but I doubt that you want to do that.
Working as a First Officer for a cargo airline is a good way to gain hours. These airlines can be shoddy operations so be careful. You will not make much money, maybe none at all, but you will get hours and get great experience. Most cargo airlines fly old, trashy planes with minimal equipment and usually fly into smaller airports. Weather is a secondary concern in many cases. In fact, a common joke is: "Why check the weather? We're going anyway." The experience you'll gain from flying old, obsolete equipment into small fields and through terrible weather is extremely valuable and will make you a better pilot! You will learn more in 250 hours of cargo flying in second-rate equipment than you will just about anywhere else. I cannot recommend it highly enough!
Now, the job I've described is difficult to find. It's a niche that hundreds just like you are willing to pay for (literally pay for a job as a First Officer). You may have to offer your services for free in exchange for the training the airline is required to give you to make you a crew member. This is not cheap as it requires the company to burn hundreds of gallons of fuel to do your flight training! Your existence becomes one of a pilot for the company...you will never drink, you'll live your life within one hour of the airport, and you will never take a vacation. For as long as you're a FO, your only purpose in life is to gain hours, nothing (and I mean nothing) else. I cannot stress this enough. Most small companies are doing you a favor by even considering you for an FO position.
It is important to realize that simply because a company makes you a FO does not mean you can log flight time! You must be flying a plane that requires an FO and the kind of flying you're doing must require a FO. For example, a properly rated pilot can fly a Metroliner as a single pilot as long as he's flying cargo. As soon as a passenger* boards the plane, that single-pilot must either have an autopilot or a First Officer. This is where you come in. A lot of these older planes have had their autopilots removed by the cargo companies! They cost too much to maintain and each pilot must be trained on the operation of each autopilot the company uses. It's cheaper to remove them than it is to conduct the training and maintain the equipment.
*A passenger is anyone who is not a required crew member. You would be considered a passenger if you flew in the right seat without being trained a First Officer. Sometimes a company employee can ride along with a single pilot under circumstances. You cannot exploit this loophole to gain experience legally, though many people do log time and "build hours" this way. The vast majority are never caught and most are told it's legal by companies selling time to low time pilots. The FAA does not seem to enforce this at all.
