Do not use Resolve or Woolite!!!!!!! They are the biggest marketed products that leave tons of residue behind when spot cleaning. What that means is that when you apply Resolve and Woolite to a spot or spill it may get rid of the spot. However as time goes on the residue left behind can make that spot "sticky". Sticky enough to attract dirt/soil to it that your vacuum cleaner will not be able to pull up. We can always tell when someone uses one of these products b/c when cleaning you will see "foamy" spots randomly throughout the area we clean.
I tell my customers to use white vinegar on many spills. You will never damage anything with trying to clean up spots with white vinegar. Hydrogen peroxide works well on some spots too. Be careful if using solvents (Example Carbona and Goof-Off). They work great on tape, gum, grease, tar and ink spots....just do not saturate the carpet as they can and will delaminate the backing of the carpet. If you have a home unit and use a solvent I would suggest flushing the spot with plain water and extracting really well then blotting with a plain white cotton terry cloth to dry more thoroughly.
I like 2 products that you can try for general spot cleaning. Spot Shot (blue container and orange container)....people on here might bash me for saying so..but this has a mild solvent in it....not strong enough to delamintate the backing and doesn't need to be flushed out. This used to be a really great product before WD-40 bought it. When they bought it they changed the formula. Its ok now. I have had customers use it for many years and they love it versus Resolve and Woolite. They other is LA's Totally Awesome. It too has a solvent (butyl I think). Its sold at Dollar Stores and is really only a buck. Make sure you dilute Awesome. It says on the side of the bottle. You can clean many things with it. Read the label!!
For pet spots use Nature's Miracle. Get it in a liquid form so it can penetrate to the backing and pad where urine will go if not cleaned up right away.
