I need some outside motivation and tips :(

I need motivation and tips so I can lose weight. I've been wanting to lose weight for a while and I can do good for a couple of weeks then I end up stopping. I mainly have two reasons one is to get healthy so I can set a good example for my daughter and two my fiancée and I have finally set a date for our wedding and I would like to lose weight to look good. I'm 239 and would like to get to at least 200.