Recruit high profile reviewers using multiple sources, e.g., personal recommendations, Web databases, published choice review
Carefully monitor the process of peer review and take steps to ensure this is of high standard
Encourage research into peer review, technological advances and reassess journal processes in the light of new discoveries
Encourage submission of quality articles to the journal by personally recruiting authors, assisting them with outreach, and ensuring the marketing plan is executed
Ensure feedback provided to authors is constructive, fair, and timely
as editor of a scientific journal, I tell you that it is very difficult to improve the general level of the articles published. If the critical mass is low, it is very likely that the average quality of published works is low unless you solicit the participation of famous people and estimated.
If a Journal is able to overcome the minimal critical mass, it is likely to increase the level of published studies also because it can discard the worst.
I think there are two areas to consider: (1) actual quality, and (2) popularity. For quality, one course of action that may help is a double-blind process for manuscript review. For popularity, as Ting Fa noted, "participation of famous people" helps. These two concepts can conflict.
For the Pakistan Journal of Statistics, it was good to have Ken Brewer on the editorial board. However, when only well-known authors are published in some journals, many good ideas are stifled, and some mediocre work is acclaimed by association. But without popularity, it will be hard for you to attract good papers and an audience.
One problem can be the length of the editorial process. It is not uncommon for that to take years. As a referee for the Journal of Official Statistics (JOS), I would review a manuscript in one round, and it might be a year or more before I saw it again - if ever. - For my own work, being in the opposite of a publish-or-perish position, I was developing estimation methodologies needed to produce official statistics, and my supervisors did not generally care about anyone publishing. It was a favor to go to a conference, and much of the work I published on the methodologies I developed to get the job done, was done outside of the workday on my own. So to document and publish my findings, I put a great deal of my work on a lightly edited online-only journal. It may cease to exist in a few more years, so that is why a friend and colleague suggested that I archive my work on ResearchGate, as I wanted a place where it could still be found. He said they expect to continue to reference my work heavily. But I could never have gotten that much on a more formal journal with the workload I had.
Recently I reviewed a manuscript for the International Statistical Review (ISR), written by several people, including one very well-known statistician, author or coauthor of many well-accepted journal articles and coauthor of a rather famous book. I have refereed or been editor for a number of journals, and I tried to provide good information for the authors, but I am rather easy in that I tend not to reject. But this paper was horrible. I wrote about thirty pages, referencing throughout the manuscript, saying what was blatantly wrong with it. However, as the topic was not well-known, if I had not been a referee, I think the editor was predisposed to advise publishing that manuscript, which could have substantially set back the field of study (a very useful, underused one) that it purported to represent.
A friend and colleague recently had trouble with a journal because there were two rival schools of thought, both legitimate, but the other one had too many supporters and would not really consider it.
Another statistician i know, shares credit, in a secondary role, for something he 'invented,' because his publication was held up long enough by one journal, for someone else to publish first. It was a bit suspicious that the person who published first had a friend at the journal that held up publication for the statistician I know.
So 'politics,' which might be considered part of "popularity," can get in the way of true quality.
My point is that if you want a higher quality journal, there are a great many variables to consider. True quality can be interfered with by 'politics' of various sorts. The editorial process needs to be adequate, but not too long, and uncorrupted. The appearance of quality, which may improve your journal's standings, may not be so strongly related to true quality as many assume.
Perhaps the best thing you can do to improve both real and perceived quality may be to gather a good editorial staff. Also, to obtain good submissions, you might need to change the scope of your journal somewhat, so that there are more papers from which to chose, which was a problem noted by Ting Fa. Finally, you may need to 'advertise' in some way, such as a session at a conference, or a 'call for papers.' I personally don't like being pressured, but the personalized requests I have received over the years, to publish in journals, etc., were welcomed, though I generally was too busy.
I hope this goes well for you and your journal. Being able to reference good journal articles is often a cornerstone for making progress.
Recruit high profile reviewers using multiple sources, e.g., personal recommendations, Web databases, published choice review
Carefully monitor the process of peer review and take steps to ensure this is of high standard
Encourage research into peer review, technological advances and reassess journal processes in the light of new discoveries
Encourage submission of quality articles to the journal by personally recruiting authors, assisting them with outreach, and ensuring the marketing plan is executed
Ensure feedback provided to authors is constructive, fair, and timely