Hey Fire Bird, although your difficulty may be caused by something you can fix, you may also want to consider that there may be some causes that are beyond your ability to control them in a practical way. I encountered similar issues with my iPad 1 which is one reason why I went ahead and upgraded to the 3rd gen.
One reason apps may crash on iPads is that they run out of operational memory. That's not the same thing as the "Storage" you see in Settings / General / Usage: it's a different type of memory that apps use while they're launched and running. (It's a little more complex than that, but that's the general idea.)
As I understand it, your iPad 1 (along with iPad 2) has 512 KB of this RAM storage. Apple doubled this in the 3rd Gen iPad to 1 GB (1024 KB) of RAM, ostensibly to help support the increased demands of its higher-resolution display.
Over time, apps have become more sophisticated as features have been added, and sometimes that increases the memory that they need to run. The recent shift to support the Retina display in the 3rd Gen iPad has significantly increased the memory needed to manipulate images in most apps (one reason there's been a flood of app updates in recent months).
As you may have read elsewhere, these "improvements" for the iPad 3 can easily have an impact on those of us with older models, because the same app with the high-resolution images for the 3rd Gen comes in the update delivered to our iPad 1s. They're not displayed in their full glory, but they still require the same increase in memory regardless.
All of this increases the "pressure" on the limited memory resources of your iPad 1, and that can easily lead to your seeing an increase in the frequency of app crashes – even if nothing else appears to have changed. Even worse, if a particular app is "close to the edge" in terms of running out of operational memory/RAM, a faster processor can sometimes keep it from dying. (In computers, there's often a trade-off between how fast the processor/CPU is and how much memory/RAM a program needs.)
Not only is the processor in your iPad 1 half the nominal speed of the iPad 2 (which is about the same effective speed as the 3rd Gen iPad), but the 3rd Gen iPad has extra processing resources to stay ahead of the increased demand imposed by its higher-resolution display. Both the iPad 1 and iPad 2, then, lose a little ground because, all else being equal, they're moving a lot more data around inside them (for those high-res images.)
Believe it or not, all this is somewhat of a simplification, because Apple has engineered some pretty amazing mechanisms into their software to minimize the impact of all this extra image data. There's a limit to how effective those techniques can be, however, so you're bound to notice the differences in your iPad's behavior at some point.
As I mentioned in the beginning, this is what pushed me to upgrade from the iPad 1 to the 3rd Gen. I saw the same thing happening that you did and understood that it was most likely something that nobody could fix in the long run. It's an unfortunate fact of life here on the bleeding edge of technology.
So, try some of the things others are suggesting (or may suggest), but keep in mind that there may be only one way to solve your problem, unfortunately.