Among other things, the UK wants the EU to pass a legislation giving greater powers to national parliaments to block EU legislation.
The UK also wants to have exclusivity in deciding how it gives out residence and work permits.
It also seeks to extend the EU's single market policies, cut down on excessive regulation and not have to contribute to eurozone bailouts.
Proposals by EU
To assuage tensions within the UK over EU membership, European Council President Donald Tusk offered several incentives including a halt on migrant welfare payments by UK to EU and assurances to cut red tape in EU economic policies.
What is the EU refugee crisis?
More than a million migrants and refugees primarily from conflict stricken regions in West Asia crossed into Europe in 2015, sparking a crisis as countries struggled to cope with the influx.
Security breaches began to occur including the Paris attacks and the attacks at Germany's Cologne railway station.
EU members began closing off their borders and following individual policies instead of EU's collective framework.
Why are EU member nations closing borders?
Tensions in EU erupted because of the disproportionate burden of immigrant arrivals, faced particularly by Greece, Italy and Hungary.
There has also been a disproportionate distribution of refugees within EU, as most asylum seekers opted for socially secure governments like Sweden, Germany etc.
This raised economic and security concerns among these nations, who feel they are singularly bearing the burden of the entire EU.
Refugee crisis: No solution likely?
EU ministers had voted by majority to relocate 120,000 refugees EU-wide. However the plan will only apply to 66,000 refugees. The other 54,000 will only be moved when governments decide where they should go, leaving room for countries to renege on their commitments.
15 Feb 2016
EU Summit to kick off amid multiple crises
The EU Summit or the meeting of the European Council is scheduled to begin on 18 February.
The meeting which brings EU leaders together at least four times a year, will focus on two themes this year: the UK plans for a referendum and the continents deepening refugee crisis.
Discussions on the economic policy of the Euro area are also likely to be held.
21 Feb 2016
Brexit referendum in June: Cameron
David Cameron has called for his referendum on Britain's membership of the EU to take place on 23 June.
He added that he had secured a good deal with Brussels to give the UK a special status in the EU.
However he also said that leaving the EU would "threaten economic and national security".
Cameron's cabinet has formally agreed to stay in the EU.