Upon arriving in Cambodia by plane, you will need exact cash ($30USD) for your tourist visa. There is an ATM there but it was not working when I arrived and isn’t to be relied on. You can get this in the airport. I recommend bringing the smallest bills possible. Ones for extra points.
I first stayed at The Siem Reap Hostel which was very enjoyable. They were able to arrange a ride there ahead of time for me from the airport. I took an amazing yoga class on roof which was donation-based and life-changing. Next, (upgraded!) to the Borei Angkor Resort & Spa. Five stars. If you are going to go for it anywhere, I recommend here.
We hired a tuktuk driver for the whole weekend. He was able to take us to Angkor Wat (we got the three day visitor passes, breaking it up to 1-2 sites per day). The temple complex is big and a ride is necessary. I recommend going to Angkor Wat for sunrise, my favorites were Ta Prohm (tree takeover) and Angkor Thom (giant faces) which are good to see during the day then Phnom Bakheng is amazing for sunset.
There are many good places to eat- check out Trip Advisor for their top recommendations.