How to prevent Tunisian crochet from curling?
The main issue with Tunisian crochet is that, since you don't turn your work, all your tension will be distributed on the same side of your project, with nothing to "balance" it and prevent the curl. Apart from blocking, all the methods suggested to reduce the curl are actually methods to reduce the tension. 

There are a lot of blog articles and videos dedicated to that topic, including this pretty useful review from Holly's Crafty Shoebox
. From what I've gathered, you should try to:


increase your crochet size
try to reduce your tension
work your fondation row into the back bumps of the foundation chain (as shown on the video)
add a double crochet row 
add a few Tunisian purl stitch rows 
wet blocking your work once finished (not so much efficient if you're working with acrylic yarn)


You might want to combine several of these tips for increased efficiency. The woman in the video by instance suggestes combining a bigger hook and working a few Tunisian purl stitch rows at the beginning and end of your project. Let us know if that worked for you!