Download a test template from a vocational training website. Unless you have expertise in vocational training, you should obtain an inventory of questions and answers from an independent source. Vocational assessment requires the ability to assess a person's personality, aptitudes and knowledge, and very few people possess enough expertise in all three areas to draft a comprehensive test from scratch. Several companies offer test templates and question inventories, and their products are often offered for free or for a small price.
Select questions from the inventory that are relevant to the students or candidates who are to be assessed. If the test is being created for a group of high school kids trying to decide what to do with their future, then select aptitude questions (e.g., math and language questions) as well as personality and knowledge questions. If the test is being created for an internal job competition process, then the test might only need to contain aptitude questions and knowledge questions relevant to the field your business is in.
Place the test questions into one of two categories: preference and ability. Preference questions are subjective, and are usually answered on a scale of "strongly agree, agree, no preference, disagree, strongly disagree." Ability questions are objective, and are answered as multiple choice or true/false questions that are graded as correct or incorrect. This will allow you to develop a coherent evaluation scheme for the test.
Place the aptitude test questions into skill categories (e.g., math, reading) and the preference questions into task categories (e.g., research, management, data entry). Test templates usually come with some sort of built-in categories, so you can base your categories on the ones that came with your test-making package.
Draw a table with four squares: likes, dislikes, strengths, weaknesses. In the likes and dislikes boxes, put the categories of things the respondent consistently expressed preference for or aversion to, and in the strengths and weaknesses boxes, put the categories on the test that the respondent performed well or poorly on. The areas where likes and strengths overlap represent tasks a person could perform well at.