These are the commands I have used.
To initialize genesis block:
$ geth --datadir ./dataDir init genesis.json
INFO [01-17|14:10:49.725] Maximum peer count ETH=25 LES=0 total=25
INFO [01-17|14:10:49.725] Allocated cache and file handles database=/home/edureka/private-ethereum/dataDir/geth/chaindata cache=16 handles=16
INFO [01-17|14:10:49.754] Persisted trie from memory database nodes=3 size=413.00B time=30.356µs gcnodes=0 gcsize=0.00B gctime=0s livenodes=1 livesize=0.00B
INFO [01-17|14:10:49.755] Successfully wrote genesis state database=chaindata hash=8fd285…6ebefc
INFO [01-17|14:10:49.755] Allocated cache and file handles database=/home/edureka/private-ethereum/dataDir/geth/lightchaindata cache=16 handles=16
INFO [01-17|14:10:49.786] Persisted trie from memory database nodes=3 size=413.00B time=22.994µs gcnodes=0 gcsize=0.00B gctime=0s livenodes=1 livesize=0.00B
INFO [01-17|14:10:49.787] Successfully wrote genesis state database=lightchaindata hash=8fd285…6ebefc
And then to start the Blockchain:
geth --datadir ./myDataDir --networkid 1114 console 2 --rpc --rpcport 8543 --rpcaddr 127.0.0.1 --rpccorsdomain "*" --rpcapi "eth,net,web3,personal,miner"
Then in geth console, I start the miner:
miner.start(1)
Now, it just hangs there. I waited for more than 40 mins but it just stays there.