If anyone thinks that MQM hold on Karachi could go than please read carefully, else be assured that chances are remote. 
To break hold of MQM, a party that wants to compete has to give first to Karachi and at ground level before expecting to get supports and votes. Rukha rukha vote mangnay say kabhie vote nahi milay ga, except from few who either wear glasses of ethnicity that blur their sight, or are young from well-to-do families who do not have much problem in life and want change for the sake of fashion, or are self-centred religious minded (do not care about others but look at everything according to their own sectarian religious thinking).
Think why MQM gets 100s of thousand votes from most Karachi constituencies, why MQM leadership do not worry of losing their votes, and why in one request millions gather to hear Altaf Hussain so obediently and well-mannered that can amaze and admire competitors and friends alike.
Well, here is tip. MQM (their leaders from top to lowest level workers) is helping day to day life of most people in the areas they control since their inception in 1980s, regardless of who people vote and regardless of MQM is in government or not. MQM helps people from party funds, regardless of whatever way they collected the fund (one may call that fund bhatta, other may call that fund chanda or donation).
You could find MQM providing food, clothing and all sorts of help to poor (also some lower-middle class), and at places even open shops selling cheaply during Ramadhan (well-off also get benefit from such MQM activities … but not as much as poor and lower middle class).
MQM gives helping hand in most problems of poor, even if that is personal. You will always find them listening and doing something if they can. Their office bearers are accessible and show much friendly attitude to their voters (rich or poor) compared to office bearers of most other parties.
They occasionally take up cleaning roads campaign and also try to do something about clearing garbage from areas, especially if they are shown concern, where even their top leadership get involved. Their party workers even try to protect people if they get threatened physically by mafias.
MQM also get involved practically and extensively in helping officials to provide service and facilitate people. One example can be seen on roads of Karachi during traffic jams. For instance, MQM has started a group of volunteers who helps control traffic if they see that traffic warden is under stress due to traffic jams (if you will visit Karachi, you may find civilians helping traffic warden in controlling traffic … you may not know who they are, but they are MQM organised workers).
Many poor in Karachi, especially MQM workers, have MQM card. Using that card they get free or cheap food items, cheap clothing, free medical treatments and free medicine (all from MQM party fund). One of my relative referring to someone who has MQM card told me that these people not only get free treatment but preferential treatment in MQM controlled hospitals, much better treatment then patients who do not have card and have to pay for their treatments.
MQM lowest level party worker has chance to rise to the level of top leadership, and regardless, if anything happens to MQM workers, party look after the family.
There are many medical doctors helping MQM in providing medical treatments free, doctors who work in Karachi and abroad (many in USA). Some doctors from abroad (especially USA but from other places too) come to Karachi every year to give free medical treatment (even operations if required) to poor in Karachi. I know of one heart surgeon from USA, who comes to Karachi ‘more or less’ every year to do heart surgery of poor who are on MQM list (he brings his own stent and that he uses in operations if required, free … though each stent cost over several thousand dollars).
Well, it is not just MQM, but in Karachi Jamait-e-Islami also do lot of social work though not at such massive scale and level that MQM does. JI helps selective few who they think are JI sympathisers (or known to JI). Another thing is that, unlike MQM, JI top leadership would not get down to floor level to help people. Worse is that, JI exploit many to work for them, but their membership is selective, and very few could become member, thus only selective few could rise to high position in JI (this was the situation when I was at University in Pakistan, and I believe situation is same today).
One can say that JI helps but selectively compared to MQM that helps poor and needy across the borad, extensively, and at all level.
There are many social works MQM does for poor throughout Karachi (actually everywhere they have presence, including Hyderabad and other part of Sindh) at extensive scale, something that is difficult to mention, and though most getting benefits are poor and lower middle class, rich also benefit from their work.
So, to oust MQM, PTI top leadership, members, supporters, workers (actually, they have to increase their workers many fold for the job), all have to stoop down to ground level, get their hands dirty with muck on roads and gutters, and then start helping poor of Karachi from their own party fund (or empty their own pocket), competing with MQM at all levels in such a way that poor and middle class of Karachi starts recognising PTI as part of them (just like MQM voters recognise MQM as their part), start feeling PTI as their party and they themselves beneficiaries as well as equals (even poor voter should start looking at himself equal to top leadership in party), seeing PTI top leadership, members, and workers amongst them as those who live with them as they live, and die with them as they die, then only PTI can expect some support from people of Karachi at ground level, else, as I can see, with time, MQM influence is increasing not decreasing, and that increase is not just in Urdu speaking people, but throughout Sindh, in all areas.
Anyhow, if PTI starts serving people of Karachi at all level with their own fund, providing same or similar facilities all over Karachi, and people of Karachi would find PTI leadership amongst them as equal just like most Karachiets find MQM top leadership as equal amongst them, then it would be nice change in Karachi, as people would benefit a lot by getting served extensively by two parties, sorting their day to day problems, competing with each other. Else, whatever little votes PTI got would erode as quickly as it came.