The vast majority of my time and energy as an assistant professor is spent trying to get funding for my lab. Without money, there is no one to do my kick-ass science. Start-up funds don't last forever, and (at least at my MRU) if you don't get an R01 from the NIH you won't get tenure. Even if you don't need an R01 in your gig, if research is a big part of your job you are probably expected to secure some sort of federal funding. So, yeah. You are gonna write applications for the big grants.
But at many places there are other, smaller pots of money that you should also keep an eye out for. These can be called "pilot grants" or "seed money" or "intramural funds". These are usually small grants, IME from 10-50K/yr. They generally last only 1 or 2 years. Just enough to do a fun experiment, develop a reagent, or pay part of a salary. In the first years my lab has cobbled together a not-insignificant amount of cash from the pilot/seed programs around here.
I <3 THE SEED $$!!
The question is: how do you find the seed money and get some for yourself? This is clearly going to be specific to your home institute/MRU. If there are any consortium or project grants around these sometimes will have funds for pilot grants. Some Uni will also use some of the money they earn from licensing IP to fund new pilot grants. You may have to keep your ear to the ground, because these opportunities tend to pop up without much warning. Another great thing is that the money can also show up pretty quickly. I have had less than 3 months from application to budget number, for example.
The applications are generally short. You need to propose a project that you can do in just a year or two, after all. It is not realistic to drop a 3-Aim R01 on a pilot grant. When I write for a pilot grant, I try to make it as explicit as possible how doing the proposed research will set me up to write an R01 (or equivalent) in the future. Most of the seed money sources that I am familiar with really want to know that they did something to start up a new project and that their money has been leveraged into something bigger.
The review of these grants can be internal, or your grant could be sent out to external reviewers. Either way, you will want to be familiar to the folks that have this kind of money and run these programs. You gotta get to know the folks that are running the big project grants in your area. Just like any other area, networking is a Good Thing. Even if there isn't a pilot grant on the line (now), you want these BSD folks to know who you are. Pitch your research program to them, and see what they think is most interesting. I have used these kinds of interactions to get an idea of how folks outside my MRU are gonna respond to different research ideas. And it is helpful to know what outside folks will think are the weaknesses, so you are ready to defend them.
There is almost nothing to lose from applying for pilot grant seed money. IME, junior faculty can be really successful in getting these kinds of funds. In fact, some of these programs are actually LIMITED to us jr. faculty. And it may be that more established researchers aren't going to go through the trouble for such a little pile of cash. But little piles of cash can be a big deal when you are starting out. You can generate some preliminary data, and get some feedback on a future Aim for a Big Grant. So, fellow assistant professors: I say, go for the seed money! Good luck