Well, I think you obviously have to look at your life objectively to decide if this would be a good time (monetarily, emotionally, etc.) to bring another dog into your home.
Then, you need to take a good look at your current dog and decide what breed/size/personality type your new dog needs to be. If you have a very laid back pup, it's probably not a great idea to bring in a very hyper-active dog. For instance, we knew exactly the kind of dog that Ranger would accept (about his same size, playful but not pushy, female).
Then I would just start looking at reputable breeders or rescues for that particular type of dog. Ask lots of questions before you adopt and make sure your current dog has a chance to meet the newcomer.
With us, our 2nd dog found us. We had talked about possibly adopting another dog in a year or so. But that's not the way it worked out. Mayzie crawled into my lap at an adoption fair (which we just happened upon), looked up at me and basically said, "I'm yours." And that was that.

Luckily, she fit all the criteria above!
But honestly I don't think it HAS to happen the way it did with us and Mayzie. I think as long as you find a dog that you know will fit in well with your family...the love will come. That's the way it happened when we adopted Ranger. We didn't even meet him before we adopted him but we asked LOTS of questions and knew he was the right dog for us. And we just couldn't love that guy more!
Good luck!