Canada has a simple calculator that you can play around with here. Basically, the higher your points the better your chance of getting accepted. Other countries are likely to be similar:
Broadly speaking, if you have a spouse with citizenship in another country, or if you're young and have an advanced degree in a high-demand field, you have a good chance of emigrating. Other than that, you're going to have to fight the odds. It will help if you speak another language fluently, for example Quebec has different immigration rules that prioritize fluent French speakers.