In my case, it is very tempting to go for a run out, since I see the problems, the patterns and positions needed to run out a rack.
But as you know, just go through a game in your mind and executing your plan are two pair of shoes.........And as I said, it is kind of hard to wrap your head around intentional misses, safeties etc. if you have open shots to go for, especially in the early stages of the game- end game tactics (3-5 balls left) is something different.
Being able to see the problems, patterns, and positions needed to run out the rack is not even half of the equation. The other part, and arguably even more important part (although both are absolutely essential), is being able to accurately weigh risk verses reward, and accurately assess what each of the options available will do to your chances to ultimately win the game, otherwise known as "playing the percentages". Acquiring the ability to accurate assess the percentages for success with each option will only come through lots of experience, however being able to be honest with yourself is an absolute necessity and can be very difficult for many to do, and making a concerted effort to pay attention to how things turn out depending on the choices you made will shorten the learning curve.
Your specific abilities and weaknesses will also have some impact on what you should do. The right choice for SVB will not always be the right choice for you because of your skill differences, but at the same time you also have to be trying to improve so that you become comfortable with the "right" decision to make in a circumstance and the "right" way to play the shot. If you always fall back on "well I am not good at speed control so I won't play the safe here even though I know it is the right shot and instead will just try to run out" for example then it is going to be hard to ever learn that safety if you won't ever shoot it now isn't it? You learn by doing, so while you have to keep in mind your specific skills, you also have to push yourself to do things the "right" way with the right plays so you can learn those skills too. When you are practicing is a good time to always try to play the "right" shots, even if they aren't the best choice yet for your skill level if it were a more meaningful match, because that is the only way you are going to learn them and become comfortable with them.
While there are always exceptions, here are some general rules of thumb for 8 ball to try to keep in mind and live by and plenty more could be added but these kind of fit in to some of the questions you have asked:
---As counter intuitive as it will sound to someone still learning the game, the guy who has the most balls on the table usually has a significant advantage in the game. The reasons why are because it is more interference balls in the way for your opponent, it is more balls for you to be able to play safe off of or hide behind if needed, there is a much better chance you will have a good shot if your opponent misses or plays safe, etc. Why on earth would you want to give up your advantage in the game? Keep that advantage until it is the right time to run out and win the game.
---Don't go for the run out until you have a pretty high percentage chance of being successful at the run including sinking the 8 ball too. You have to be able to be honest with yourself in your evaluation.
---Go for your problem ball (the one that will be very tough to get good shape on) as soon as possible in your run. If you fail to get good on it, try to get on it again as soon as you can. Saving problems for the end of the game usually leads to disaster because if you fail to solve it when it is one of the last balls you are now out of options and chances, whereas when you go for it early, you will likely get several chances to try to solve that problem throughout the game if needed.
---Try to solve your problem clusters as soon as possible in a run for the same reasons as above, because if you fail to break it out properly early in the rack you may get more chances, but once that is all you have left you are up a creek in a bad way.
---Whenever you get ball in hand you should almost always try to take care of your biggest problem on the table, whether that is a ball that will be extremely tough to get shape on later, or whether it is a cluster or some other problem. Even if you are going to have to play safe with ball in hand, try to do it in a way that takes care of your biggest problem if at all possible (say by moving your "tough to get shape on" ball into a better position, or breaking up your problem cluster, etc), and if that is not possible try to take care of your second biggest problem instead and so on. Sometimes the best way to address an issue while playing safe is through indirect means such as hitting one of your balls over near say a problem cluster so that ball now becomes a good key ball to break out the cluster from as you pocket it on some later turn. Sometimes with ball in hand you may want to take a shot before playing safe even when you already know you have no intention of trying to run out yet, such as pocketing your "really tough to get shape on" ball before playing safe with with the second shot as that may be the play that best increases your chances for ultimately winning.
---As has been mentioned previously, with every turn at the table you are trying to do something that is going to increase your chances for being able to win the game, so always look for those opportunities. Don't be satisfied for example with just looking for a good safe that hides the ball for your opponent, but instead look for a good safe that also solves one of your cluster problems or other problems. The examples here could be endless and you really have to analyze the table to find these opportunities. They don't always exist but a lot of times they do but aren't real obvious and you are going to miss them if you are not looking hard for them.
---While you always want to improve your situation with every turn at the table if possible, keep in mind whether or not it benefits your opponent as well. If it benefits him as much or more than it benefits you, like breaking up some clusters might do for example, then it may not be the proper shot or the proper time to take it.
Add in an opponent who will give you a second chance 90% of the time and yeah...you have the "I will pot myself out of this somehow"- player.
Just as your play will have to take into consideration your own skills, it also has to take into consideration the skills of your opponent. The right play against strong player and a weak player can vary as well.