What substrate are you using?
I used to have those colored gravel from LFS, and it was a pain trying to plant on it. Basically I poke a hole with a finger, plant the plant, use one hand to hold the plant in place, use the other to replace the gravel displaced by the finger. I also do this when the tank is 1/2 to 3/4 full, and I put water in it slowly.
Now I have AS Amazonia 2, much easier to plant and grow using it. It also helps that I have this long tweezer like tool to plant or uproot.