Doing one by one: which one first and how to do it?

Today I struggled again in making decision. I know that I am not good in multitasking and some studies also show that it is not effective. So do one by one is the option I chose. Next question is which one first? Especially as we are aware that time is not enough to do all things in the list. This is where I often mix up into one and lump two things at the same time, which one to do first and which one not to do (maybe not to do at all). Then I tend to stuck and not doing any part of it. 

The reality that I need to accept is that there is no perfect decision. I know that I have the tendency to regret whatever I decide and that is ok. Or at least it is a separate problem. So it is not realistic to expect to choose an alternative that does not have the down side. This includes on the alternative on how we want to do that work. At the end we just need to choose and stick on that. If it turns out to be wrong and we can still change it, then change it. Otherwise, bear the consequence knowing that the other alternative has similar risk. This is because the thing that I am indecisive typically mean they are similar weight of priorities. Otherwise I will just choose it like there are certain food that I don't eat. It is only when they are ok then I have the problem to choose. So that means they are ok too. Well the priority or the weight may be wrong but that is also a separate problem. Let's do one thing at a time. Remember, the worst alternative is to stand in the middle and not choosing or keep postponing without any clear deadlines.