Perestroika is typically more strongly associated with the economic aspects of Gorbachev's reforms, with Glasnost etc. covering the political aspects.

In terms of the economic changes made:

• Enterprises were essentially made more independent. So they had to balance their accounts (income/expenditures), rather than just make whatever they were told to and then get bailed out if the money ran out. This reform also gave enterprises a bit more control over who much workers got paid.

• Enterprises, instead of providing products to whoever was designated in the plan, were allowed to form their own contracts for goods with other enterprises. This also meant that enterprises didn't have to just produce what they were directed to by the plan and in theory could better cater to consumer demand.

• De-facto smaller scale private enterprises were allowed. In principle they were cooperatives but in practice the collective management/ownership aspect wasn't always adhered to.

• Foreign investment was encouraged through offers of joint enterprises with Soviet enterprises.

• The foreign trade monopoly was rolled back, meaning it wasn't just the state doing the purchasing/authorising all trade.

In practice enterprises still failed and still had to be bailed out - after all if too many enterprises fail you end up with higher unemployment and production issues. Price controls remained, which meant that while enterprises still had some latitude in what they could charge, it still didn't always reflect what people were willing to pay or how much it really cost to make. Foreign investment never really took off for assorted reasons, which meant the additional capital, expertise etc. never eventuated.

I think the simplest way to summarise why these reforms didn't work out is that while they broke down the old structures, they didn't actually do anything to facilitate the creation of new ones. The guys running these enterprises didn't always adjust well to the new circumstances. After all they got to their position by being 'good' at running an enterprise in a planned economy. Other structural issues in the economic/industrial sector, like aging machinery preventing producting of newer/better products, were still there unaddressed.

Some sources:

• Alec Nove, An Economic History the USSR 1917-1991.

• Archie Brown, The Gorbachev Factor.