@Wenceslas,
What interests do you have? A hobby or a sport? You could join a co-ed softball team - you could take an art class or photography, wine tasting, etc. Find an adult education type program - one that has "fun" classes - like the above I noted above. There will be a variety of classes - I once took a pasta and sauces cooking class - we were put in groups so you do have to socialize as you learn to make a particular dinner and then get to enjoy it after.
There are travel clubs, hiking clubs, biking clubs, etc.
This way you get to do something you like or are interested in and haven't tried and then meet new people that share your interest. More likely to find a girlfriend by making friends that have similar interests. Also it would be lots less pressure and easier to engage in conversation.