Hi
Some things you can show them are
1) A return ticket
2) Letter from your employer in your home country saying that they expect you to be back, that you are important to their organization, how much you are paid.
3)Show them you have property in your country, that you own it.
4)Bank accounts in your country
5)Travel health insurance
6)Show them that you have parents, siblings, relatives etc.. in your home country
You just need to convince the officer you will leave Canada, I think if you show those things I mentioned you'll have a case. However sometimes it can be very tough, even with a strong case they can refuse people, because they think that no one wants to leave his or her spouse and go back to a developing country. As its difficult for people to live apart from their spouse.
You might get a visa if you have a really good job and are paid well, then they will think that this person is unlikely to leave his job and is likely to return.
There is no magic bullet, you just have to try.
