if I start with
./litecoin-qt 
for solo mining 
->
how do I see that there is something going on?
TIA
If you're gonna solomine, you'll need to use either a third-party miner like Lolcust's Tenebrix Miner, or ArtForz's fork of cpuminer. Alternatively, you can add 
gen=1 to your litecoin.conf, or launch Litecoin with the 
-gen flag. If your CPU-usage goes up to about 100%, it's probably mining.