IF ONLY...

wish / if only

We can use wish and if only + past simple to express a wish for something to be different than it actually is:

• If only I could lose some weight. Then I'd be able to wear this dress.

• If only I had more free time. I'm sure I'd be less stressed and more cheerful.

• I wish I were younger. I'd love to be able to play tennis like Roger Federer.

• I wish you could drive. Then I wouldn't need to be your personal chauffeur.

Note that we also use wish and if only with the past perfect to express a regret about the past, a wish that something might have been different:

• I wish I'd had more children. Then I wouldn't be so lonely now.

• If only you'd told me you felt lonely. You could've spent the summer with me.

Note that the shortened forms of I'd had and you'd told in the above examples are abbreviations of the past perfect:

• I wish I had had more children. Then I wouldn't be so lonely now.

• I wish you had told me you felt lonely. You could've spent the summer with me.

Source: http://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv347.shtml