Some nights it might simply mean sitting down a player if one or two player's attentional capacity is affecting the whole team's performance. I find it productive to ask my players very specific questions about events on the court or in practice in order to get them to concentrate. The same is true of defensive footwork, or passing errors. Ask them specifics and you will get better concentration. Play players who do concentrate and sit players who do not.
Players are quite alert to factors that affect their playing time in most cases.
If they see that mental errors or lack of focus cost them court time they will focus more. Demand more concentration by your verbal feedback to your players. Finally, use time pressure to force concentration. Less time means you must concentrate better, execute more cleanly and perform under pressure. If you team reaches a certain level of competency in a timed drill, challenge them to perform it 5 seconds quicker with two more baskets as an example.