As far as I know you have to combine them. I even think you need to lose small amounts knowingly so that the other person thinks you are strict about your hand. If you only bet on the good hands than the opponent will not bet when you have a good hand and increase the pot. However, if you mix it up and both bluff and play on good cards and intentionally lose money all those three combined would make you unpredictable and when you invest a high amount the other side will never know if its a sure thing or not. In some sense, poker is for experienced gamblers. Newbies are recommended to start by watching professional poker players.
I think mixing the options is a great strategy however you need to make sure you only bet big on the ones you have great hand.
Do not go in all the hands thinking you will either bluff or lose intentionally, just bet on great hands and put up a small amount on just decent hands and when you have horrible hands try to not bet as long as possible, if there is no bet increasing on the table of course you can just sit and watch the game with your bad hand but if there is bet increasing and you have a horrible hand there is no point of bluffing or even intentionally losing with that hand.
Do what you said but with either great hands or decent hands at worst, never do it with horrible hands.