Progress is not inevitable!
It only seems that way because our modern civilization has created a positive feedback loop that continually increases the pace of technological progress. Prior to the various revolutions within the past few centuries, there are plenty of examples of individual civilizations whose technological progress stagnated or even regressed because one or more of the factors import for innovation was lacking.
Key Factors for Innovation
The following is a list of factors that can contribute to innovation (some of which are discussed further in other answers). Understanding these different factors will allow you to craft a scenario that best suits the world you are building.
Surplus
Put simply, to develop technology effectively civilizations need extra food and other resources. Innovations will be sporadic and difficult to retain if you do not have individuals who can dedicate at least a portion of their time to learning and experimenting.
Necessity may be the mother of invention, but scarcity is often the bane of innovation. When resources are limited, a civilization will need to use them towards survival. Thus, in dire circumstances, it's exceedingly difficult to develop technology to overcome the situation; instead, it's more likely that people will adopt different practices using similar (if not inferior) technologies.
Motivations & Incentives
Though some individuals are natural innovators, the majority of people need some form of motivation. Competition, be it nations warring against each other or individuals participating in a free market, is a great motivator, but it is not the only one. People may also innovate for the sake of prestige, to promote humanitarian efforts, or enable creative expression. Too few people will develop technology if there are no incentives to do so.
Cultural Acceptance
To ensure technological progress has a meaningful impact, a society must be open to innovation. If the majority of people are hostile, fearful, or even just apathetic towards new technologies, they will not be adopted. Furthermore, those who do try to expand the civilization's intellectual and technological capabilities will, at best, be ignored and, at worst, persecuted.
Communication Networks
Establishing networks of communication is vital to innovation for numerous reasons. Communication can expose individuals to diverse, unique, and inspiring ideas that they were unlikely to come up with themselves. It enables collaboration so that innovators can build off of each other and coordinating efforts (as opposed to working in isolation on the same technologies). 1006
When two or more civilizations communicate with each other, it expands the pool of possible innovators and provides a means of retaining knowledge should one civilization fall.
For much of history, this was accomplished through friendly trade and diplomatic exchanges. War may be a motivator for innovation, but peace is an enabler.
Natural Resources
Many technologies cannot be developed without access to the appropriate resources. Animal husbandry would be impossible without animals that are suitable for domestication. Metallurgy is completely impossible without metal ores and nuclear physics would be nearly as impossible without sufficient quantities of radioactive materials. These resource dependent technologies are often the most vital to expanding a civilization's capabilities; it's difficult to imagine a modern world without such resources.
Literacy & Education
The value of literacy and education is two-fold: first, it significantly increases a civilization's ability to retain knowledge. Secondly, it enables more people to be innovators. The more widespread these are, the better!
Historical Examples
The following are just a few examples to illustrate the above points.
Lack of Surplus, Lack of Motivations & Incentives
It's worth mentioning that the first civilizations to emerge were agrarian societies that settled along fertile river basins. These were by far the easiest places to produce surplus with limited technology.
Civilizations that lived in other environments would not be able to generate the same level of surplus. Meanwhile, non-agrarian civilizations lack incentives for innovation. If resources are scarce or your neighbors are hostile, you can readily move.
Lack of Cultural Acceptance
As for stagnation, one example (as mentioned in another answer) is China. It had the potential to initiate the Industrial and Scientific revolutions. However, the government actively discouraged innovation as it was seen as a threat to the stability of the nation.
Similarly, Arab scholars were not only responsible for retaining much of the knowledge past civilizations (including the famous Greek philosophers that Europeans would later celebrate), but they made a number of important advancements. Unfortunately, the sentiment that scientific pursuits were contrary to the teachings of Islam grow to the point that the various Muslim academies were shutdown.
Lack of Communication Networks, Lack of Natural Resources
In the Americas, civilizations like the Aztecs and Incas emerged. They were reasonably complex, but geography and lack of natural resources greatly undermined technological development.
The Aztecs and Incas were contemporaries, but they were far too removed from one another to effectively establish trade. 1006