Have employee or more employee meetings on retirement savings aka a 401k meeting. Keep the investing fresh on their minds maybe even monthly inserts with the paychecks. You need more to contribute and more to contribute more.This is what I do as well.
I have an interesting investment problem that just came up again this year. I contribute the max into 401(k). However, at the end of the year when our plan goes through testing we fail on the ratio of contributions from highly compensated to non-highly compensated employees. Therefore, I get money returned to me, both my contributions as well as earnings on those contributions. Its not all of my 401(k) contributions but just a portion. This year its about 24%. That will get reported as income in this tax year and taxed accordingly. This has happened every year for the last three years. I have been taking that money, increasing it by the taxed amount and then putting that into an investment account to try to keep my investments whole but I still loose out on the employer match portion. Interested if this has happened to others and if anyone has a better idea than what I am doing to combat this.