A fixed value, relative to what? To a fiat currency? In which case, should it be US dollars, euros, yens, yuans...? Relative to a commodity such as oil or gasoline of some quality? Relative to gold, silver, platinum, diamonds? A basket of all the above? All of these have very variable values and both the reasons of their intrinsic volatility and the possible remedies for that are far above your capabilities.
Creating a crypto-coin with a "stable" value relative to whatever you want to track it to (for tracking it absolutely to yield a fixed value is impossible, unless you control the other stuff) depends not on the crypto-coin's algorithms per-se but in the market - you'd be forced to create an exchange of last resort and be willing to spend a lot of money fighting people who'd try to move the price way too up or too down on purpose to cash a quick buck after the distortion, or simply are trying to attack your coin to destroy it or harm you. You'd need very deep pockets, much technical expertise and a lot of luck.