First thing to do is apply for preference points for every species this year. Then you should pick an Over The Counter unit near Denver and spend as much time hiking and observing as you can this summer. It doesn't matter which unit - they all have elk. Then pick up Matt Dworak's excellent book, "Public Land Elk Hunting" on Amazon and read it twice. Also read every thread on the Bowsite elk forum. Many of the best archery elk hunters in the world are on there and will share ideas and help you with specific questions.
Good luck, and go do it!
Always glad to see young people getting started bow hunting!
Jaq gives some great advice above.
I would add to that to start networking with bow hunters in Colorado.
One of the best ways to do so would be to join the Colorado Bowhunters Association (CBA). The annual Banquet is coming up very soon in Fort Collins. It is a great event to meet and greet some great bow hunters that will have a massive amount of knowledge about bow hunting in Colorado in one room. The CBA also have a big gathering and bow shoot in the summer called the Jamboree that is well worth attending with even more bow hunters coming together for a great weekend of camping and bow shooting. There are other 3 D bow shoots around the state that are awesome networking opportunities. CBA will have dates and locations for their shoots on their webpage.
If you are interested in traditional archery, you should consider joining Colorado Traditional Archery Society (CTAS). The CTAS banquet was earlier in February, but there is a great 3D shoot in the Flattops in June.
There are a number of archery shops and clubs along the front range and a few scattered through the mountains with local League shoots that are a great place to learn more and meet people as well. Several clubs have permanent ranges set up that you can go out and shoot any time with your membership. I was a member of the Golden Club when I lived down near Denver and it was a great range and club. Ask around at your local bow shop about options near you.
Read everything you can get your hands on for hunting to learn strategy. Get yourself up in the hills as much you can to start learning what elk and other animals do and how they act and react.
It has been a very long time since I made that first elk and mule deer bow hunting trip to Colorado from Central Texas on my own when I was 19 years old. Learned the most through networking with other bow hunters here in Colorado once I was able to move here not too many years after.
Good luck!
Excellent replies from Lou and Tavis and I, too, recommend Matt's book. He is on the CO forum also.
Plus there are a ton of other expert elk hunters on here.
Good luck in your quest.
And like Lou said, tell us a bit more about yourself.
PECO's Link