(Mark 4:3-8 13-20)
When I read this verse, I think that I better make sure my ground is fertile and soil is rich and ready for the 'seed'(Word), so I know it will grow strong.
But wouldn't this diminish the gift of grace with this thinking?? Doesn't this seem like we're earning it, by cultivating ourselves before receiving Gods seed? So then we could say, "I only grew because of the work and fertilization I put into the soil(self)", giving us reason to boast in ourselves?? This is not The Way!
Don't worry I'm going somewhere with this :)

Did you know that back in ancient times they would first break up the soil, throw the seeds upon it and THEN plow the fertile soil behind it?
You see, the seed would first be planted on rough, broken up soil. Then the rich topsoil and fertilizer would follow.
So stop worrying and making excuses for not accepting His Word. I know this can be difficult to do, I do this too! (I think this is why I'm not baptized yet, for this reason!)
We feel that we first got to...get better at this or that, be more giving, find a good church first, stop swearing so much, stop smoking, etc....the list goes on and before we know it, we want to do all the work ourselves so no credit goes to God!!
By saying these things, you're really saying that His grace isn't enough. I think it's a natural human view point(and error with grace), thinking we need to earn it ourselves. But grace and ungrace don't go together!
Get that seed planted, accept that seed into your broken up heart and body, let God water it and his servants help fertilize it.
WARNING
Don't just let your seed sit there, exposed to the elements of this world. Seeds have great power in them to grow into strong plants, bearing sweet tasting fruit and roots that can crush through rock and cement. But the seed itself, when first planted, is quite delicate. Not enough attention can cause it to wither and die. You don't fertilize your seed with rocks, the sun will heat those rocks burning the seed or young plant. You don't want to overwater your seed, creating a stream of water that lifts up your seed, floating it away into a weed patch.
Accept the seed and let God do the watering and His Word fertilize you. Pray to God for help if weeds are growing around you, let God do the weeding. Rely on God, he is the Good Farmer!