People that lost a lot of weight relatively fast, any tips?

I’m on a journey toward an healthier body and weight loss. I’ve lost around 15 pounds (7 kgs) in one month and a half. I plan to lose more and I plan to keep up the rhythm, as much as I can.

My question is : any tips regarding the potential side effects of such weight loss? And anything I should expect/prepare for? I’m thinking loose skin, muscle lose, etc etc.

I’m looking for the kind of thing that would make you say: I wish I knew that before I started loosing weight. Or: I wish I’ve done that as I was loosing weight.

Any tips/insight are welcome, particularly from people that went through a similar experience.