Do check your work with portlint before you submit or commit it. portlint warns you about many common errors, both functional and stylistic. For a new (or repocopied) port, portlint -A is the most thorough; for an existing port, portlint -C is sufficient.
Since portlint uses heuristics to try to figure out errors, it can produce false positive warnings. In addition, occasionally something that is flagged as a problem really cannot be done in any other way due to limitations in the ports framework. When in doubt, the best thing to do is ask on FreeBSD ports mailing list.