As the leader of a high-performing team, how you distribute and balance work across the members of that team is a critical success factor. It needs to be done fairly. Note, I didn't say equally. Work allocation needs to be done fairly because you want your team to operate on the basis of equality. You want people to work on things they're good at but also that they're excited by. There are five criteria to think about as you think about distributing work.
Consider the work's priority. Priority needs to drive everything. If you've been rigorous in your prioritization process, start at the top of the list and begin allocating work from there. That list should be based on the team's and the organization's goals. This has to be the first consideration in terms of how you distribute work. If a project is a top priority and somebody is available to do that work, they should be tasked with that work.
2. Skill Sets
Evaluate the skill set of the people who you're thinking about distributing the work to. If they have the right skill set, you're going to get a high quality result. The end product will be something that meets your customer's needs. This also reduces the likelihood of people failing because you're not giving them work that they don't have the skill set to perform. You're giving them something they can be successful with.
The next consideration for allocating work is a person's availability. All things being equal in terms of priority and skill set, who is free to do the work? Who has the bandwidth? You should not be shifting resources from one project to another when you have available resources to pick up that new project.
If you start shifting resources around between projects when you have available resources elsewhere, you're going to lose momentum on that first project and that project might fail. Additionally, the people who are on the project are going to be very frustrated. They had the resources they needed and all of a sudden they don't. It's going to seem like it was at a whim to just move somebody around. The person who will be most frustrated is the person who has the resource taken off the project they're succeeding on and put onto something new.
Next, you have to think about the development opportunity this project might present for that person. You should be constantly upgrading your team's skill set. A way to do that is to give them new work where they're going to learn new skills. Put them in situations where they're going to be a little bit uncomfortable. Give them projects where they're going to have to step up and learn, be taught, and be open to feedback and coaching. That's how you're going to take your team to the next level of performance.
The last consideration in terms of which person gets the work when it needs to be allocated is does somebody have an interest in performing that particular task? If someone is really interested and passionate about a project, you should let them take it on. They're going to be motivated, excited to do it, and hopefully their performance will follow. One caveat here--make sure people don't only gravitate to the work they enjoy doing and they stay away from things that they're not comfortable with. If you let that happen, they're going to end up getting pigeonholed and they'll be very narrow in their focus.
Go allocate some work
If you think about all of these considerations as you distribute work across your team, doing so will ensure you tackle the highest priority projects with the people who have the right skills to do it. The work will be balanced in a way where you're going to execute the project but at the same time you're going to develop your people.