Are you really stuck about where you want to do your work experience? There are a number of choices you will encounter: public or private sector, training given, large or small firm, salary, experience available etc. A top tip is to leave open as many options as possible, especially when you start looking, as you never know what could be offered.
Finding an internship or placement, no matter how long, requires some work on your behalf. Firstly, you need a strong CV, then you need to find companies you are interested in and either fill in their online application form or send them a speculative application.
Limiting your possibilities to only one or two placements could be a little risky. It doesn’t take an economist to work out that if you apply to several organisations you are more likely to be offered an interview.
Finding a placement is much like finding a real job. If you have successfully been chosen for interview (well done!) prepare some ‘model’ answers. After an interview, it is likely you may have a day at a training centre where assessors will watch you. Obviously, all companies have slightly different interview procedures: large firms often have training centres whilst smaller firms may have a relatively informal interview process.
Economics is a diverse and varied subject allowing you to go into many different areas. In terms of finding a placement, this could be more of a hindrance than a help, simply because there is too much choice! Apply for a few (making sure your cover letter is company-specific every time) and see what happens. Try your university’s Career Service: they will be able to give pointers in the right direction. Also, try scanning the internet: this can be laborious but rewarding if you find what you want.