I've recently found myself often in the following situation in the deepstack live tournament I managed to chip up to 3 times more than average at early stage of the tournament ( usually before the ante kicks in- level 4). Then I start to open up my range a little wider when the ante starts and blinds gets bigger which i thought it is the right strategy, but often i found i lost chips bit by bit especially when most players are 3 times chips less along with a few shorter stacks (less than average) on the table, either i double up the shorter stacks or i lost a big pot to average stacks. no matter what i do it went down the hill i couldn't chip it up again and end up busted before the end of the day. that's exactly what happened to me last week, the fact is if i had walked away from level 4 when i had nearly 100k chips, i would still have more than average chips by the end of the day ( the average chips of day2 was 90k ).Please help me what the right strategy is if you have a big stack at the early stage of the tournament, how to maintain the chip lead, continue playing well without losing chips? 

Your thoughts are much appreciated