1. Where do you buy your bitcoin from
From Bitonic.nl, a well-known website in the Dutch crypto-community.
2. What exchanges do you use
Bittrex nowadays. Used to be Cryptsy and BTC-e a while back. Then switched entirely to BTC-e, and eventually moved my activities to Bittrex.
3. When you buy alt coins and profit, do you convert back to btc? Because what if your profit from alt coins and convert it to bitcoins but bitcoins is low, doesn't that defeat your alt coin profit?
I do. I'd rather see an increase in value relative to Bitcoin than a higher value in $$$. However, in an ideal scenario, both values go up.
4. Do you convert from bitcoin to usd to withdraw? If so where do you withdraw and which method do you use.
No, I withdraw via Bitonic.nl. I send them Bitcoins and they pay out the corresponding value in fiat on my bank account. In my case, Bitonic is both an entry and exit point in my trades.
And yes, the fees are pretty severe nowadays. Bittrex deducts 0,001 BTC per transaction, that's $4,4 nowadays ... !