"Congress and CPM will be ousted and NDA governments will be installed in all three states we are quite confident," Mr Sarma told NDTV on Friday.
He said the strategy is "simple." In Tripura, where Chief Minister Manik Sarkar of the CPM has been in the top post since 1998, the BJP will partner with a regional party. "We will have alliance with Indigenous Peoples Front of Tripura (IPFT) and we will oust CPM. So we can see a BJP-led government in the state immediately after election," he said.
In Meghalaya though, the 48-year-old leader said, the BJP and its current partners will contest separately. "All partners will contest elections independently but we have decided for a post poll alliance like in Manipur."
In Manipur last year, the BJP won fewer seats than the Congress in assembly elections, but quickly stitch post-poll partnerships with regional parties to form government.
Sources said the BJP's ally the National People's Party is strong in Meghalaya and the BJP does not want to contest the elections as a junior partner. There are also several Christian-dominated seats where the NPP feels it will be at a disadvantage if it has the BJP as an ally.
The parties will be careful not to cut into each other's votes, the sources said, adding that while the strategy worked in Manipur, the allies could be walking a tightrope in Meghalaya, where the Congress' Mukul Sangma has been in power for the past decade.
Amid a rebellion in the party against Mr Sangma's leadership, the Congress has seen a steady attrition in the last few months with several of its legislators resigning and walking over to the NPP or the BJP ahead of the elections; a latest batch of five joined the NPP earlier this month.
The ruling party, which had 30 MLAs in the 60-member assembly, now has 23.
In Nagaland, where the BJP-backed, Naga People's Front-led Democratic Alliance is in power, Mr Sarma said his party's strategy is "stability."
While he is "101 percent sure" that the BJP and its allies will form government in the state "with the Congress nowhere," the party is trying to ensure a reconciliation between senior regional leaders. "While former chief minister and MP Neiphiu Rio is an old friend and prominent leader, Chief Minister T R Zeliang and NPF chief Dr Shurhozelie are influential leaders, so we are working out on how we can get all of them," Mr Sarma said.
The BJP had imported Himanta Biswa Sarma just ahead of the 2016 assembly elections in Assam from the Congress. It was a bitter parting with Mr Sarma accusing now Congress chief Rahul Gandhi of preferring to play with his pet rather than grant audience to unhappy partymen from Assam who flew down to Delhi to meet him.
He regularly makes sharp attacks on Mr Gandhi and is on a mission to systematically annihilate the Congress in the north east. He delivered Assam, Manipur and Arunachal Pradesh for the BJP.
Elections in Tripura will be held on February 18, while Meghalaya and Nagaland will vote on February 27. Votes will be counted on all three states on March 3. All the states have 60 assembly seats each and a party needs to win 31 or more to form government.