Many decisions in the game will be given to you only if you have saved up gems. Gems being the premium currency the game uses. You can save those gems simply by being conservative. Change your clothes? Nope, I'm saving cash. Gems are hard to come by so for many situations it's worth saving and you won't miss much.

But of course, that doesn't mean you should avoid using gems at all. There will be plenty of opportunities to do so, you should just be selective about the moments you really want to see. Save up those gems, and when a special moment comes up, you can spend without hesitation. It's all about smart spending decisions. Just like in real life. Which is why you need advice.