How can I get a better tan...?

I'm a guy and it's really weird for me to ask this but what is the best way to get a tan outdoors? My best friends each work during the day and I work at night so there isn't much for me to do during the day. I have been just sitting inside watching Netflix but everytime I went to work all my coworkers would be really dark and I just feel out of place and I want to be tan for my senior pictures in couple of weeks. So a couple of days ago I started to layout in my backyard (so nobody could see me.) I've laid out with sunscreen on and with it off and I've only gotten a little dark. It's been hot here lately and I want to use it to my advantage. When I was younger I used to get dark by barely being outside but it seems as I get older it takes longer. What should I do to get darker?