I'm using Milliput this is some really great stuff, it's a two part epoxy putty that air drys and no heating it to harden needed.
Tools needed Hobby knife and spatula tool.
So mix up two equal parts together until it has a uniform color and now your ready to work.
I take a little of it and roll it in to a little rope/worm.
Then wrap it around the base and cut away the extra.
I then press it all in and around the base with my fingers, don't worry about finger prints we will make them go away.
Next using a flat edge tool I cut the extra away from the base.
Then with very little water I use my spatula tool to smooth everything out.
Now set it aside and let the putty harden.
Now they are ready for a base coat of paint and painting.
I like the looks of a just plain old base without anything like ground cover or clumps of grass, Being that I don't like the looks of clumps of grass on the base when gaming in an urban areas or any build up area in general for most part and what little gaming I do in the open fields or woods is somewhat limited and still has a nice look to them.
This is not saying that if you like the look of ground cover and clumps of grass on your bases then I say go for it, the idea here is to help those who wish to make better looking bases for just that.
When finished the bases will be painted with a medium gray color, which works very well for me and I really like the looks and it allows your finished painted figure to stand out a little more.
The extra putty not used at this time is not going to go to waste, plan ahead you can make sandbags and other things with the extra putty.
I know this may seem very basic or that is something that every body already knows but, not everyone dose know and there is not many tutorials out there showing the next generation of gamers as to how.