There's the saying "Dress for the job you want, not the job you have". This goes for streaming, as well. If your stream LOOKS professional, it will be treated as such by potential viewers, especially if you carry yourself professionally, as well. I've had very little time to actually stream, but I have put some time into getting at least an overlay that looks okay, setting up TwitchAlerts, and setting up a bot in the channel to take care of spammers and the like.
You don't have to be a graphic designer. There's free layouts you can get. They don't look the best, but they're better than nothing. That being said, you COULD put some time into trying to learn some basics of using Photoshop/Gimp/whatever and trying to make a layout.
Also, I know there's some differing opinions about whether a webcam is important, but I actually think it is. I don't know if anyone can say that having a webcam is detrimental to your stream. People want to see your face and your reactions. They identify with it more. That being said, I'm broke. I wouldn't be surprised if many potential streamers are, as well. I don't have money for an actual webcam. I do, however, have a smartphone with a camera. I use an IP webcam to broadcast my camera feed from my phone to a local IP and do a screen cap from VLC (can also do it from a browser, but it seems to take more resources doing it that way) that's viewing the network feed.
There's lots of little tricks like that one can do to make their stream more professional and more complete. Don't have the money for an expensive green screen setup? Get a green sheet from the Goodwill. It's not about the quality of the board behind you. It's literally just the color. Don't have the money for expensive lighting? Hit up instructables.com and google for tips on jury rigging more studio-like lighting with what you have, or at least with some very cheap components. Want a mic stand but don't have the money for a pro setup? Go get some PVC pipe and make your own for next to nothing. There's guides on how to do that all over the net, as well.
Get creative, too. People love to see streams doing things they don't see anywhere else. Pay attention to your chat. Talk to them, play with them, if possible in the games you play, provide them with additional features outside of twitch, even if you're not partnered. A website with a forum is a good place to start. Sure, if you don't have thousands of viewers, it'll probably be slow. But, that's okay. It's still there.
Look into bots that do fun things in your channel, as well. Don't go overboard and try to gauge what your audience might like, but there's lots of options for fun bots. Your chat is an IRC channel. I'm an old school internet guy and have spent LOTS of hours on IRC in the past. It can be a cool, fun place to meet people and do things even while you're not streaming. There's lots of IRC bots out there that provide games chat can play either while you're streaming or not. Encourage people to hang out while you're not there and talk to each other. I actually think that's something streamers could do a little better. IRC channels can be valid communities all on their own and have been for decades. Twitch channels should be no different.