The best way to protect your RV from sunlight and weather is to put in a garage or at least under a carport. However, those are not viable options for many RV owners. Not everyone has room on their property for an RV garage or even a carport and construction costs can be very expensive. Structures have to be extra tall to accommodate most RVs.
The next best option is an RV cover. Some folks make due with tarps, but they have definite disadvantages. For one thing, they don't really fit your RV. A second problem is that many tarps prove to be somewhat abrasive where they contact RV surfaces. And they don't breathe. Sure, one of the purposes of any RV cover is to protect the rig from rain and snow, but RV covers are made to be breathable so moisture trapped under the cover can escape while tarps are nearly waterproof and will trap condensation inside, which can be detrimental to the unit being stored.
As fall approaches, it is just about time to start planning winter storage for your unit. If you don't already have an RV cover now would be a good time to measure your unit and start looking for a good value on an RV cover to fit it. Custom made covers will fit the best, but will be the most expensive. I purchased and off-the-shelf universal cover of the right size for my 36' Holiday Rambler Vacationer and have had excellent results. It fit quite well. Even the zippered door was exactly where it needed to be to line up with my RV door.
Covering your RV with a tarp, while not ideal, could be better than leaving it exposed. Try to avoid having the tarp contact any painted surfaces where it could rub the paint away. Stake it out so it is secure but leaves a little room underneath for circulation to prevent condensation and moisture buildup. Making a framework of PVC pipe to hold a tarp up over an RV might be an affordable way to get fairly good protection without the problems associated with having a tarp in contact with the RV.
Installing an RV cover can be quite a project. It works best if you have an extra person or two to assist you. Unpack the cover and determine which end is the front. You may have to lay it out on your driveway or in a parking lot to find the front. Then re-roll it from the back. Carefully get it up to the roof of your RV. If you are comfortable with the weight you might be able to carry it up while climbing your RV ladder. If not, climb on upon the roof and use a rope to haul the cover up. I like to start by laying the rolled cover in the center or the roof near the back of the RV, then unrolling it all the way to the front before spreading it out and down over the sides. Be sure to remove or flatten any antennas or other obstacles that might poke holes in the fabric before rolling it out. One way of dealing with things like roof vents is to put a plastic tub up-side-down over them to support the cover. Once the cover is fully extended down all 4 sides of the RV get down and pull it snug and, if it has a door zipper, try to align the opening with the RV door. There are usually straps on the front and back to snug it down and ropes to pass underneath the unit and tie off on the other side. You don't want to pull it so tight it stresses the fabric anywhere but it should be snug enough to keep it from flapping in the breeze. If you are using a universal cover, make sure the zipper for the door is on the right side before you tie it down. You may also have a little bit of leeway to adjust the cover to line up the zipper with your RV door.
Keep the cover clear of debris while it is in use. That usually means getting up on top of your RV and brushing leaves or pine needles away periodically. Accumulation of debris can hasten rot and can sometimes add weight that puts unnecessary stress on the fabric. Snow removal is also a good idea if and when it can be done safely. You might want to try clearing snow and other debris from the roof by standing on a sturdy ladder beside your RV instead of walking on the covered roof. Trying to walk on the covered roof can damage the cover and can be dangerous. You might trip over obstacles hidden under the cover or be tripped by folds in the cover itself.
If your RV is stored anywhere near trees, frequently check to make sure no limbs or branches have fallen on to the unit and damaged the cover. Carefully remove offending sticks and patch any holes they may have made in the cover. Small, temporary patches can be made with duct tape. For more permanent patches sew small tears and use similar fabric to patch larger holes. Sometimes you can scavenge patch material from the storage bag if your cover came with one.
If you run your RV now and then while in storage (as you should about once a month), be sure the cover is clear of the tail pipe and air intakes. The same thing applies to the furnace and water heater if you need to use them while the unit is in storage.
Removing your cover in the spring is another strenuous task. Once again, having an extra person or two to assist you is usually very helpful. First, sweep any debris off the cover. Then unfasten all the straps and ropes, then make sure the cover is clear from bumpers and mirrors. I usually pull up one side and drag the whole cover across the RV and drop it onto the ground on the other side. You may need a second person to guide it away from bumpers and mirrors as you pull it off. You will want to find a flat, fairly clean space to lay it out to roll it. Driveways, parking lots, and grassy areas are usually good candidates. Don't lay it on a wet surface and make sure any pavement is free from oil stains. Stretch it out from end to end, then fold both sides over to the center. That will usually make a roll about 6' tall so, depending on the space you have to store the cover, you may want to fold it over again. That will give you a shorter but much fatter roll. I usually go with the taller, thinner format and stand it up in a plastic trash can for storage. Remember which end you start rolling from so you will know where to position it on the roof the next time you install it. If you start rolling from the front, you will want to unroll it from the back and vice versa. Keep a brush or broom handy to brush off any debris from the roll as you go so you don't trap garbage inside. Dirt and debris left in place during storage can cause staining and premature wear. Once is is all rolled up, tie it off with rope or bungee cords to keep it from unrolling. Store it in a clean dry place. You might want to put some moth balls and mouse traps in and around the cover to keep pests out.