A member of my family was homeless in Sydney for a few weeks last year, afflicted by mental health problems. It took a psychotic episode before he finally got help, firstly with the mental health problem but that allowed him to rent cheaply in a country town and keep a roof over his head. A year later he is just getting back into the workforce on a part-time basis but years of neglect of teeth, for instance, means he doesn't eat properly until they are fixed and that requires money. Addiction to cigarettes and (previously) alcohol doesn't help. This family member is fairly typical of the homeless though has family support now he's back closer to home, unlike many who have no family support at all.
So the answers lie not just in providing housing though that may well prevent the downward spiral in mental health. It involves a host of support staff including psychiatrists and dentists.
Having said all that, homelessness comes down to a question of demand and supply and ever-growing population means supply cannot keep up with demand for housing. Slow population growth and you go some way to solving the problem, though not all the way, of course.

As part of Campbell Newman's shock-and-awe razor gang tactics, his government has sold off two Brisbane caravan parks, which is a permanent home to 300 elderly people. Those people are now effectively homeless.

http://www.couriermail.com.au/news/campbell-newmans-caravan-park-sale-could-leave-300-people-homeless/story-e6freon6-1226440719737

Several caravan parks have already gone, or turfed out their permanents. More are set for closure, not just from Newman's razor gang, but from greedy local councils who wish to sell them to developers to turn them into unit blocks and resorts for the rich to either stay in or invest in. These parks not only provide affordable permanent accommodation to many of our most vulnerable people, they also provide a combination of independence and a close-knit community at a time of life when both are very much needed.

Similar sell-offs are happening with halfway-house accommodation, as developers buy up inner city properties.

There is no point in governments throwing money at the homelessness problem with one hand, while indiscriminately selling off low-cost accommodation real estate with the other.

When talking about our homeless, we should remember our 55,000 street kids. Without practical help, these young people are effectively on the scrap heap before their life begins.

Without education, they will be unable to get a job, marry, or enjoy the normal things the average Australian does.

First their hygiene goes, then their health, with considerable lowered life expectancy. This is absolutely tragic.

Whatever the reasons they are on the street, and there are many, these are our children. What visible assistance are they being given?

the fruit of secularism at work again. The breakdown of the natural family has led largely to this crisis. The numbers on the street will only increase as the 'rights 'of individuals to have sex with whomever and whenever is promoted through secular dogma and children are denied fathers and mothers. The selfishness promoted by secular dogmas through the last 40 years has produced the inevitable result. Secular Governments are not prepared to stand against what has caused this problem so will leave it to others to try and give some comfort to the victims.

Just think. The Money to solve all this is right under our noses. Stop the flow of Aid money overseas & cut back on aid to the boat people. Most of this money is wasted on Ceo's Salaries, Accommodation & 1st. Class Travel anyway. The 5 Billion Dollar industry is a scam anyway.

Old sayings; "You can't help others if you can't help yourself", "Charity begins at home", It's about time the Australian Government, of any persuasion, started doing something other than mouth off.

That being said 1.
There are a lot of impediments to helping the homeless. The biggest impediments are the very people who run the schemes for the homeless, but it's not entirely their fault. I put the blame squarely on the shoulders of those bastions of Political Correctness. You can't call "a spade a spade" for fear of offending someone. So the system tippy toes around everything & no-one does anything in fear that "someone" may be offended & they will be sued for saying the wrong thing in "someone’s" eyes. They all cry "someone" should do something. It's all BS.

That being said 2.
The people we are dealing with. Warning, I'm not PC but I'll try to be as delicate as I can be. The greater percentage of these people cannot & never will be helped. They suffer from a range of mental & physical incapacities. They should be in special homes, like old people’s homes, so they can be helped. I don't mean houses in the suburbs I mean special facilities like old people’s homes. Separate ones for the disabled & mental naturally. This way they can have supervised contact with the normal world & have their needs attended to in an appropriate manner.

cont...

...cont

The lesser percentage are people in flux. Lost jobs, lost accommodation, inadequate schooling, or, just plainly need to be taught the skills in how to survive in the real world. Hygiene, cleanliness, tidiness, making the bed, cooking, washing up, putting things away, manners, etc. We've all seen horror stories about bad renters on TV.
I reiterate. Stop the flow of Aid money overseas & cut back on aid to boat people.