Analyzing Closed End Funds

Anybody do this? What factors are most important to look at that would be different from a normal company? Please advise.

Premium/discount to NAV.

also fees, leverage, transaction costs, market impact (lot of them are thinly traded), portfolio management changes or protential changes

Yield, Volu, Leverage, Prem/Disc to NAV, Its like an ETF/Mutual fund

Thanks for the responses. Anything from a fundamental perspective? The level of detail available in their filings seems pretty thin.