Firstly, the peasantry. Embrace land reform as much as possible. Tsar Nicholas is going to need to restore as much credibility with the peasantry as possible after 1905 and this is the most ideal way to do so. The peasantry will support anyone who supports land reform, and enacting widespread land reform will check rural revolutionaries. The farms likely won't be the most efficient, but that comes later. Also, abolish the land captain system: peasants see it as a continuation of serfdom and it has no real benefit. Replace it with a dedicated rural police force recruited from the local area and give them enough funding to be effective. Place them under strict commands to always address people by the formal 'you' in Russian. Also, connect accepting the new police system with land reform. as that would be really the only way to make it palatable to a peasant populace used to solving matters with their own form of (often brutal) justice. The old governor system with nobles appointed from Petrograd is abolished. They will be elected.
Secondly, industrial workers. Bringing this group onto the side of the Tsar is going to be difficult. Many of the industrial workers lean Socialist, especially after 1905 and the sabotaging of Father Gapon's non-communist religious trade union movement and the fighting during the 1905 revolution. Best bet is to try and improve the workers rights in the country and provide avenues for affecting change. Legalize strikes and crack down on attempts by businesses to crush said strikes. Put pressure on companies to compromise with workers. Also work on improving sanitary conditions. Clean the streets, minimize outbreaks of waterborne diseases through sewer systems. Also, court a movement willing to cooperate with the Tsar in regards to workers rights, primarily through...
Courting the Duma. The Duma established post 1905 was consistently undermined by the Tsar, who held widely known contempt for the legislative body. If we are to optimize Russia in this time he would have to court the deputies in the Duma, especially the SRs and the Kadets. A working relationship needs to be established wherein the Tsar constantly meets with and discusses matters of policy with leaders of all parties. Nicholas needs to make sure that the Duma holds actual responsibility and feels as though it influences the course of the state. Otherwise it will become a glorified tribunal for the Tsarist state. Through cutting the red tape that purposely stifled the growth of businesses in Russia and the granting of political freedoms, the liberals would likely be satisfied with the Tsar. Through those and the policies I listed in the paragraphs above, the socialists would be sated for now. Also, Nicholas needs to give up political power. He is no longer the Supreme Autocrat of All the Russias. He is the Tsar of Russia, with the same powers as the German Kaiser. This with a copious amount of symbolic and not so symbolic acts aimed at improving Russia's image. The Peter and Paul Fortress, the 'Russian Bastille' is destroyed by Duma suggestion and its prisoners freed, things like that.
Minority policy. Stop Russification. Allow for freedom of religion and emancipate the Jews. Allow for publications to be written in minority languages and mandate that officials in a given region actually know the language of the people they govern. Give regions such as the Baltics, Poland, Finland, the Caucasus, and maybe Ukraine the same rights Finland has. Even give the Poles a separate state that shares Nicholas as a monarch. Crack down hard on pogroms and political violence. Keep anti semites out of office and prevent things like the Beiliss Affar from happening.
Foreign policy. Don't even think about starting WW1. Concentrate on staying at peace.