Analyze if it is useful. Does the criticism offer some insight to you about your writing? Not all criticism will be useful, even if it is constructive. Constructive criticism is only useful if it helps to improve your writing.
Take what sounds good and discard the rest. Some parts of the criticism might not be useful to you; but as a whole, it can offer some way to resolve a particular problem you’ve had or enhance something you’ve only hinted at. Take only what is applicable to you and your work.
Experiment. Try to do things differently. If the criticism offers a different way of fixing a problem, try it and see how it works. Nothing, especially in the draft phases, is set in stone. If it doesn’t work, you can always experiment again.
Make adjustments. If the criticism offered goes to the heart of your story (it’s theme or character development, for instance), then you need to take it seriously. Use the criticism to fix whatever problems you might have in your story or use it to re-think your story outright.
Ask questions. If you have a particular problem or issue with something in your piece, ask beforehand for criticism or advice. This will particularize the criticism you receive and make your workshop experience more helpful to you.