A certificate says you attended. A project gives you twenty minutes of material in an interview — what you built, what you chose not to build, and what you would do differently. Interviewers ask about the second because it cannot be memorised.
Finished beats ambitious
A small project that is complete, deployed and explainable is worth more than a large one that is eighty per cent done. Half-built work invites the one question you cannot answer well, which is why it stopped. Scope down until you can finish, then extend.
Messy data is the point
Tutorials use clean datasets because they are teaching a technique. Real work does not, and the ability to handle inconsistent dates, missing values and duplicated records is a large part of what an employer is actually buying. The briefs here use data with problems in it deliberately.
Write down the decisions
For each project, keep a short note of what you tried, what failed and why you chose the approach you did. That note is what turns "I built a dashboard" into a conversation, and it is the single most underused thing in junior portfolios.
Two strong beats six adequate
A portfolio is averaged rather than maximised by whoever reads it. Two projects you can defend in depth read as competence; six shallow ones read as somebody who follows instructions. Cutting your own work is uncomfortable and it is part of the skill.
Every brief states its deliverable before it states its steps, so you know what finished looks like before you start. Each one also links to the course it belongs to, if you would rather build it with a trainer looking at your work than on your own.