REITS

I have investments in individual stocks, Index funds, t-bill, regular savings. I want to find something that is more risky than the Index fund but less than the stocks. My son said his friend’s father was talking about how great he was doing in REITS. I looked this up and understand basically what they are; but, what should I be looking for in the economy as far as when or when not to invest? Like now, with mortgage rates relatively low, but probably (?) not going lower, is this a good time, e.g. refi’s are slowing down. Does anyone know anything about the in’s and out’s of REIT investing?