1. adjust the cable if you want it to engage closer to the handle. It will be a bit sloppy towards the end.
2. If the gears don't engage with a quick stab then the dogs on the gear box are not aligned, stomping on the shifter won't change this, you need for the gears to turn a little. My general approach depends on if the bike is running or not. Not running I apply a little pressure to the shifter and rock the bike a little. drops right in. If it is running, say at a stop light, I again put a little pressure on the shifter then let the clutch out just enough to start to move the gears a bit and it drops right in.
True enough these bikes don't have the slick shifting of a modern gearbox, but coming from the clunk of an old "airhead" BMW it seems quite normal and to me. Time and practice will make it second nature, in a while you won't even think about it.