Printing advice

I recent ordered an 8x10 print of a photo of mine. It was the first time I've had anything printed other than a family snapshot and the first time I've printed larger than 4x6. It's a low-key photo and I was concerned the exposure wouldn't turn out right so I attempted a rudimentary monitor calibration using a test patten I found on line. I thought I had my monitor adjusted fairly well and I spent a long time working on my raw file to get the exposure just right, but the print turned out much darker than I wanted it to be. I'm going to have to try it again. I'm wondering if anyone has any tips (short of buying a monitor calibrating instrument) to help me ensure I'm going to get the result I want on my next attempt?