If you have an Android phone, look for the app "
Ham Test Prep", I used it and passed Tech and General in one sitting. I only studied for 2 days (Thursday and Friday, tested on Saturday), but I did have prior radio experience from Civil Air Patrol that helped with the basics. There are other practice test resources, but I liked how this one presented the questions. Master the Tech questions before starting on the General material. If you're feeling frosty you can study for Extra as well, but that's a lot to learn in a brief period. For most people, Tech is all they need, but General gives you almost all of the HF bands for long-range comms should you need (or eventually need) that capability.