SCHUFA questions / strategy

The subject of student housing has often been mentioned here. Most Universities have some student apartment facilities but they are usually limited. But foreigners are generally given priority since they know it is easier for locals to look on their own. Foreigners won't know the local market and will be at particular disadvantage in a housing market that is very tight in most of Germany - although I don't know about Duisberg in particular.

The majority of students will find rooms in a shared flat with other students or young people, known as Wohngemeindschafts or WGs. This is by far the cheapest and easiest way. One often needs no Schufa score. They will generally make a rental contract out as a sub-renter with the main renter. And since students come and go there is a constant turnover of places available. The thing is usually to find the matching place with people with similar life-styles. Not sensible to be a neat, quiet, studious post-graduate student of 35 living with a bunch of chaotic,  loud, partying 20 year olds.

Usually such rooms get found through word of mouth or ads stuck on pin-boards at the Universities. Problem is that most University buildings are presently closed or have very restricted access because of Covid and the pin-boards are not being used. In Stuttgart at least, I think most courses are still being taught online. Maybe through a university one can find some website, chat-rooms or what-ever where one can find such things online.

But unless one gets really lucky, they might have to arrange an air-bnb, hostel or cheap hotel until they can find a room.

I'm by no means an expert o the subject but as far as Schufa goes, one doesn't do anything themselves but will have a schufa created for them by a financial institute upon getting a loan of any kind; not sure about just having a bank account. One builds up the score by borrowing and repaying loans and mortgages or using credit cards. Contradictory, one who never borrows or uses credit will not have a positive schufa score. So it is not a grading of ones actual financial situation as a billionaire could have no schufa score. It is a rating of one one's record of paying money back on time that was borrowed. I have personally never needed to even know such a thing while living in Germany for over 20 years. I bought my own apartment and took a medium sized mortgage for 10 years that was paid back on schedule. Otherwise, I never took loans or credit. There is a kind of freedom of information act that one can apply and find out for free what their schufa rating is but I have never bothered.

First and foremost: Don't use "Rentberry" or similarly websites!
I had a look at it and found that it is merely a consolidator of ads from other sources, some of them dubious. Better search on Ebay Kleinanzeigen (without realtor), Immoscout (mostly with realtor -> you pay a fee!) or WG-gesucht (for rooms and shared housing). Or follow Tom's advice above. You cannot start your search before arrival in Germany, and most places are advertised and taken months before move-in, so it is prudent to have initial temporary accommodation to cover this period - but two weeks might not suffice.
The SCHUFA is a law unto itself (some say a "Mafia") and there is very little you can do to establish or improve your listing there, other than having a (financially) clean record as Tom stated above. As student, without fixed income, you are anyway at the bottom of their (and most landlords') ranking, so look for places that don't require it (it is by no means compulsory!).
I have also never needed my SCHUFA record, but got one once a couple of years ago out of personal interest. I found that it contains most (but not all) of my bank accounts, most (but not all) of my mobile phone contracts (even prepaid ones) and my mortgage was curiously missing. It also contained an allegedly non-paid bill (of less than €10), which I never knew about, but no information about my income. It is also their well-guarded secret how all this is calculated into an overall score (I had the second highest possible), but apparently how many and which enquiries about my score they receive is playing a big role here. In my opinion, this is unsuitable to base any decision on, so as a landlord I never ask for it from my tenants.

Thank you for your responses :-)
Much appreciated.
I was wondering one quick question, if you want to purchase home goods, in France they have le bon coin and in the uk we have gumtree, what is the German equivalent?
Best wishes,
Rob

You mean a classified ads site where you can find cheap used goods?
Try Ebay Kleinanzeigen!