Finding the right idea for a game can be quite tricky. As a rule of thumb, find something to be excited about and something you might want to play yourself. A good motivation is playing games and finding bits and pieces that you really like or that can be improved. One thing is for certain: do not clone. Don't make clones, make something original instead.
Finding game ideas
Probably the best way to find game ideas is during game jams, where you get to develop a game in a very short time frame. One of the more popular ones is Ludum Dare (http://www.ludumdare.com/compo/) and Global Game Jam (http://globalgamejam.org/). The first one is an online solo competition whereas at Global Game Jam you have to work in teams. What both game jams have in common is a theme that is provided and should be used by all entrants.
For a less competitive approach, you might also want to check the Twitter
@PeterMolydeux, which is a parody account of Peter Molyneux, the creative mind behind Fable, Black & White, and Populous. There are tweets about completely crazy and/or funny game ideas, most of which would be very fun to play.
The kind of game we are developing is something a bit like an action game with role-playing game elements. The player is going to control a ship full of pirates who are waiting for ships to attack, seize, and scavenge.
After each mission, we'll get back to the pirate cove and buy better items such as cannonballs or hire a more experienced crew. Our game will be called "A Practical Survival Guide for Pirates". However, as the name is long, we'll just leave the game template name as "PirateGame".
The most important thing when developing is to remember the scope. It's very important to keep the scope as small as possible; in most situations, you still have to cut gameplay elements out in latter stages of the development cycle.
So saying we are going to create the next Angry Birds with more levels is probably as unrealistic as saying we're going to develop the next World of WarCraft just with more weapons and quests.
Let's put our goals and expectations into a list. The following is the list of goals we have for this book:
Finished game by the end of the book
Gained an understanding of development with Sparrow
Examples are relevant for game development and working with Sparrow
Most independent games generally focus on a single mechanic and polish it to the maximum. Tiny Wings and Snapshot are good examples.
As with all software, there is always the danger of becoming a feature creep, which means adding all kinds of features during development without planning for it or balancing. In the end, the game might have all the features we want, but these features might be mutually exclusive and the game might not be fun.
So keeping in mind the scope and limitations, let's make a list with our features and gameplay elements for our game:
Attacking enemy ships
Collecting loot from enemy ships
Upgrading ship equipments
Hiring new crew members