MidiPrefix has as great blog post. It's a little dated, but it's a must read for any mod-team.
It really got me to thinking about how mods keep on re-inventing the wheel. Constantly new mods startup, create a few great models of an MP5, maybe a tank or two, and then disappear. Why? Because the fans aren't excited. And the reason they're not excited is because there are tonnes of mods that have the same concept art, and the same few select models. Even if a modder has a great idea, he might get discouraged from the lack of attention he's paid for his hard work.
So how does a modder get around this? Well there are a few ways.
What I mean by this, is that the modder has a whole new idea that's outside the realm of a new weapon model and a new tank. Before I get any flaming comments, let me be clear: You are not automatically uncreative simply because you're (at this stage) reinventing the wheel. For a lot of mods it is necessary to do this to accomplish their goal. This leads us to the second way...
If the way your mod is setup is that you have to (re)create some weapon models, make sure you're willing to go through with it. You're not going to get a lot of attention at this stage of development. So this means you have to be willing to go without the fuel of fans, or that you're part of a great synergetic team.
3. Being part of a good team.
If you're part of a good team, lots of problems just magically disappear. You get the synergy of simply being near other productive people. You get the encouragement of other team-members. And the whole process at large is made a lot more enjoyable, and productive. A "good" team varies widely by definition, and by the scope of your project. It might be 2 or 3 of your best friends, or it might be 10 or 20 new-friends. Being part of a good team might also mean you get to share the "boring" parts with other members.
All in all, it's a catastrophe that this happens to so many mods. There are lots of pitfalls in the development process, and this is just one of them.