How are you supposed to realistically build websites and apps so companies can target users if you cant target or define your own users appropriately?

You need to define a target and then you can build a plan. That means figuring out what you are first and being realistic about your capabilities and who your direct competition is and what they charge. The market may not be able to bear the premium you are charging. You might need to think about offerings that are flat rated and lower in price in order to remove any objections for the prospect to give you the order. Maybe it's pitching a range of options and selling the premium.

One of the first questions I'd ask is what businesses need websites or apps? What businesses are willing to pay for the premium of your agency vs someone else? What tangible value are you really adding compared to those competitors? This narrows the scope of where to target and prospect.

If you're building apps, I'd imagine getting in front of local developers is a good idea. I'd also imagine targeting new businesses for websites and app development is a good idea too. Are there local professional groups or business organizations that meet? Get someone out there advocating for the company and building a network. It's always easier to give work to a guy you know.

You can also look up listed businesses in specific segments by a host of variables. Say you want to target medium sized business with 50-100 employees in technology, or medical. You can do that. You can even bring it down to a specific region or geography. The more you know what you're looking for, the easier it is to find it and design a plan to get in front of those people. Is that handing out pens or USB drives at a meeting or renting a table at a tradeshow or placing an ad in a specific trade magazine? I don't know. You're going to have to figure out the ways you hit your target.