To increase sales, do you prefer increasing targets or putting an attractive commission scheme supported with a smart marketing plan?

It depends if you have if you feel that potential is more and you are making less sales then you need to increase targets and the sales team will expand its coverage boundaries but if you feel that there is need financial motivation and then your team will spark up for more sales then you need to increase their commissions, but it all depends on the observation and analysis that what is required.