Abstract and conclusion first, and after, if you find it interesting then you read the whole paper. My advice is to write a summary about each paper your read in a word document for later reference. you can also include in a table the Title, Author name, and key findings of the paper.
I read the the full paper if the results are interesting after going through abstract and conclusions. Some papers are to be studied in full if it is necessary for your research work.
If the research article interests me, at first, I read the abstract and, going a little further with the question, at the end, I read the last part of Introduction.
In a scientific article, first of all, I read its abstract. . In this part, the author represent what he had wanted to achieve through his study. Therefore, this part of the article should be written more carefully. If I would be interested on reading more details, I pass through the part which indicate the material and methods and then at the conclusions.
Title and abstract must have be read first of all to see if they are in agreement and after that, I read the methodolgy and if it is adequate for study model, so I read the rest of the paper
Title will attract me towards a paper, I first read abstract to understand the whole theme of paper. I will go for conclusions to see the results of the process/ methodology..