Why five? Let's look at some ways. I assume you mean with a loving partner? A relationship with a child, parent, boss, employee may equally need help but I'll assume it's a partner. Firstly have you checked out, jointly, what you both want out of a relationship? This one thing could take several evenings of discussion and if you find that you have different desires or expectations from a relationship, why bother to go onto the other possible four or fourteen ways of improving it? It's doomed.
On the other hand, the very fact that you ask suggests that you are committed to improving things. Check out whether this commitment is joint. If so, the next step is to list areas of dissatisfaction. You see-- we're heavily into relationship work already. Never mind the 5 things.