will for me it was spaming the hell out of the housing where you have like 3 houses instead of one.. i put down the infomation thingy and built the food for them and finally built that bridge on the other side of the island on that first map.. i also made it to the moon so i spam a lot of that there. if you at that level then u have all those pieces. to make the investors. i did do the level up houses thingy too.. the U key and then shift=u i think to get them to level up.. i am at work so its kind of hard to really remember all of that from last night but i did make it to level 25 or 26 now. pm me if you need more deeper details maybe i can share a video or something.