Sometimes stress is caused by a single source of pressure, but more often there are numerous primary and secondary sources of pressure. One of the basic steps towards reducing stress is to pick your battles and ignore or avoid unimportant stressors. Even small distractions can compound a primary source of pressure and so result in a tangled web of stress that looks more menacing than it is.
Find the source of your problems and cut away the fluff. Clarifying the situation usually does not solve the problem outright, but it does provide a handle on how to grasp it and reduces the accompanying stress.
Another simple and straightforward tip is to attempt to reduce stress while experiencing it. For example, the stresses of a long day's work can be alleviated a bit if you remember to take a deep breath often. This helps physically as the body can relax for a short while, and also mentally because you are less likely to become caught up in an unnecessary treadmill.
Reducing stress is a temporary solution, but it can be a big step in the right direction.