Assess the overall condition of the card. Look for any scratches, loss of gloss or folds. Take a good look at the corners. The straighter the corner the more valuable the card.

Look at the font of the card. Check the centering of the baseball card. The card's picture should be centered in the middle of the card. If there is a border, it should be equal in width all the way around the card. Many times a card my be off center due to printing issues.

Understand the rating system for baseball cards. The main categories for baseball card ratings are Mint, Near Ming, Excellent, Very Good, Good, Fair, Poor. Cards in perfect shape are considered mint, and cards with slightly fuzzy corners or off-centering are considered near mint. Excellent cards have issues such as a fuzzy corner and surface imperfections. The lower levels will categorize cards with more issues and they tend to not be worth much.

You can look up the value of the card in a price guide. You can find a price guide from a newsstand and look up the value of the card. When you find the price for the card, then factor in the condition of the baseball card. A mint card is worth 100 percent of the price guide value. A near mint card is worth about 50 percent of the full value, an excellent card is worth about 20 percent of the value, a very good card have about 10 percent of the full value and any card that has a rating of less than very good is worth about 5 percent of the full value of the price guide

You can also get the card professionally graded. If you have a card which you think might be exceptionally valuable such as a rookie baseball card, or a rare baseball card, have it professionally graded by an expert to get the actual value prior to trying to sell it.

Don't forget that there are many people that don't realize the true value of their card. It is possible to get a cheap baseball card by buying a card from someone that isn't interested in its value.