Play less often, but buy more. This increases your chances for that specific play.
This strategy does not affect your odds of winning in your lifetime but can affect what jackpot you win, if you win.
Instead of buying a ticket every week save up the money you would spend and use it to buy tickets when the jackpot reaches large amounts. This maximizes the return without increasing your financial risk.
Play as often as you can, with the same numbers, every time. It's not about which numbers you pick, just as long as they are the same ones. Patience is a virtue.