There is definitely merit to going after larger companies, after defining and prioritizing your markets; obviously, the more narrowly you define your markets, the more effectively you can target those markets.
Here's the example I always use, because it's so easy to understand.
Pretend I'm a realtor. We meet at a business meeting, and you ask me what I do. I reply that I'm a realtor. Or, I might reply that I'm a residential realtor. Or, I might reply that I'm a residential realtor who deals in homes valued at a minimum of $750,000.00. Or, I might say that I'm a residential realtor who deals in homes valued at a minimum of $750,000.00 within a fifty-mile radius of my office.
What have I done here? I've consistently narrowed what I do and whom I want as clients. That's what narrowly defining your markets is all about.
While it might be logical to determine to go after larger accounts, there's also a downside. You don't want too few clients/customers, so that you have too many marketing eggs in too few baskets. Then it really hurts when one of those precious few leaves.
So, it's fine to go after bigger accounts. It's not sensible to go after those that are so big that the sales cycle is at least six months, they make you feel as if they're doing you a favor by working with you and they're painfully slow pay.
Look at your current base. If you're working with companies of ten employees, go after those with 25. Just don't try to make the leap to those with 100. For one thing, they might not have the confidence that you can handle them properly at your size. For another you might bite off more than you can chew. And what about your other clients? How neglected will they begin to feel?
Remember, the single biggest reason that people or companies change vendors is Lack of Attention.
Acquiring significant new business and having to hire another person are a wicked combination. You don't know if you're coming or going. That's why it's a good time to prepare a Marketing Plan (www.azobleassoc.com). This Plan should help you move gradually. It should emphasize doing business via referrals and generating additional business from existing clients.
Who knows? The clients you feel are too small might well need other services you offer. The big question is, do they know everything you do? How much business are you letting slip through your fingers, by not educating them over a period of time about your various products and services? When you hear, "I didn't know you did that," it's a real punch in the stomach; and you don't stop beating up on yourself.
You might well be on the right track; but move cautiously, and be sure to have a Marketing Plan. You'll make more headway far sooner at a pace that's right for you.