You are having a problem on using "determine" in a sentence because you have got the meaning wrong. Well you are trying to use determine in the context of "to make a decision about something" but actually determine means "to find out something".
I just typed determine in google and it spit this out so just read through the meaning and synonyms of determine before you continue reading this answer (sorry for the extra work)
It might be a bit confusing at first, so I will try to explain it to you with a simple example
Lets say I am building a wooden table and I must choose/decide on the right type of wood to be used. I can decide if the wood is hard enough to do the job or not, but if I try to determine if the wood is strong or not the answer is yes, the wood is strong but that does not mean that it is suitable for building the table so I still have not decided if the wood is suitable or not.
So in the above scenario I did find out (determine) that the wood is indeed strong, but I cannot still decide (choose) if it fits my requirements.
Coming to your example/question, you asked "but I don't know if it's the right way to say 'determining/deciding' " but determining is not equal to deciding that is the problem. Decisions can be affected by personal preferences but when you determine something it is a simple true or false irrespective of personal preferences because a fact is a fact.
Coming back to the sentence you provided -
determine a blog which has a high score as a recommendation blog
split the sentence in two
Part-1 : determine a blog which has a high score - Determine/find out which blog has a high score
Part-2 : as a recommendation blog - Decide on whether it should be the recommended blog
So the sentence can only be part 1 or part 2 or a compound sentence such as Determine/find out which blog has a high score and Decide on whether it should be the recommended blog.
The fine point in this lengthy answer is "Determine is different from Decide and you cannot replace one with another".
P.S : The answer given by user3169 answers the rest of your question regd 'as' or 'to be'.