With respect to a first publication, how would the following factors affect prospects (in academia, as well as in research-based industry)?
Whether or not the publication is in a top-tier journal. Of course, I realize that the better a journal, the better. What I mean to say is, given that I have some work now (such as, for example, observing certain trends when a simulation is run on a high performance computing cluster, and explaining any anomalies that arise) which may be publishable in a non-top tier journal, and some other work (which works towards providing improvements to a recent paper) which has a chance of faring better than a non-top tier journal, but which will take more time to get ready (say, 6 months more?), is it worth waiting for the completion of better paper (i.e., the paper which may get into a better journal)?
Like in 1, given a choice between publishing as a non-primary author now, versus publishing as a primary author later, should I wait to publish as a primary author later, and only then submit the journal in which I am not to be a primary author (assuming, of course, that the primary author has no issues with waiting).
Would it matter if one's first paper is in a journal or a conference? I have heard that it is better to send a paper in for a conference before a journal (especially for a first paper), since conferences tend to give much quicker replies. Am I correct?
Does the content of a first paper matter? Whether it is a review-based paper, a paper suggesting improvements to an already existing paper, or a paper submitting a reasonably novel idea? Assuming of course, that other methods or ideas would eventually be published, should I, say, wait to propose something more, umm... novelish first?
Long story short, how much would my first publication (in terms of parameters such as reputation of journal, how much it goes towards improving knowledge in the field, whether or not I hold primary authorship and so on) affect my prospects (whether in the industry, or in the academia).
NOTE 1: If it matters, this question is with specific reference to Computer Science (a little more to the applied side than to the theoretical side). Also, I am an undergraduate.
NOTE 2: By a journal of less repute/non-top tier journal, I do not mean to say a disreputable journal, such as a predatory one, merely a journal with lower impact factors, higher rates of acceptance, et. al.