This forum is full of great advice to people considering buying a motorhome for the first time. If you have the Budget is often an important consideration. Toedtoes advice above is some of the best I've seen. Take the time to work back through the advice threads and "stickies" at the beginning. There are different types of motorhomes, i.e. Class A, B, and C. If you have looked at the three types and think you want a Class C, this is your forum. There are a number of current brands each of which offer different lengths, and floor plans and different prices based on gas vs diesel engines, luxury levels, etc.
There are a number of recently produced "rigs" that are available used but discontinued. There are high-end brands that are almost custom built with higher quality materials, they cost $10K+ more than other mass produced brands and have better resale value. Water damage due to leaks in roofs are a major problem with motorhomes. Some brands have less leak prone roof construction and materials. Tires older than 4 years old become unsafe and must be replaced
despite appearance and tread depth. Good brakes and cooling system must be maintained. These factors become important in buying a used rig. With a new rig, you and are protected by chassis, housebox and individual appliance and device warranties for a period of time. Extended warranties are not generally worth the extra cost because of loopholes and exclusions. Take your time deciding what you want, whether to buy new or used, length, floor plan, brands, features, etc. Don't give up and buy on impulse. Don't be overawed by RV size. You will find that a 27 footer is almost as easy to handle as a 24 footer. Rear bed rooms with RV queen beds are better for adult sleeping comfort than sleeping on convertible sofas, dinettes, or in the overhead. Slides are nice but add to overall weight and can have electrical/mechanical and leakage problems.