Propose an asset allocation suited to what the investor wants to achieve and the limits they face, and defend it

Start with the investment policy statement: required return, ability and willingness to bear risk, time horizon, liquidity needs, tax position, legal and regulatory limits and unique circumstances. Identify which approach fits (asset-only, liability-relative or goals-based), then screen the candidate allocations. Eliminate any that breach a constraint, such as insufficient liquidity for planned spending or a shortfall probability above the stated limit; among the survivors choose the one that meets the return objective with the least risk, or the highest risk-adjusted utility. A good justification ties each key feature of the chosen mix to a specific client fact. The trap is choosing the highest-return portfolio because it meets the return target while ignoring an explicit risk constraint, or the reverse.