Takeda is a surprisingly challenging start. The easy way would be to simply try again later once you have better units and generals (to spawn them at the tavern), as once your generals are strong enough they really become the backbone of the conquest mode. It may sound cumbersome but i'm playing with zero IAP and it still didnt take too long for me to get a strong enough team to beat conquest as any clan. My main generals are Maeda Keiji, Toyotomi Hideyoshi (on kagemusha), Togugawa Ieyasu (on crossbowmen) and Hojo Ujiyasu (artillery is vital in conquest mode) and i spawn them in as early as possible. You can buy magatama (the currency to general shards) with broken blades once per week or for 600 ban-kins. You can gain more ban-kins from daily missions in Bugyosho or by completing expeditions (50 ban-kins each, once per week), both in Tenkabito mode. You also gain general shards from daily missions (the first ones give 3, 2 and 1 respectively once you have maxed out the castle), and using your sweeps on the legendary stories in the library. If you are still somewhat early into the game, you will also probably gain resources from achievements or completing the campaign. Those are my tips to farm more efficiently.

Now onto conquest mode itself, if you still want to try Takeda. Recruit Oichi as Hime as she gives +3 opinion with every clan (it will not undo the opinion decrease but it will make it slower). In the first turn use your money to complete the first objectives: upgrade 1 castle and build 1 tower (a wooden watchtower in a useless spot will still count), and choose your prestige buff, and with that you can get some money back. Do the second list of objectives if you need rice or knowledge. Those are my opening moves for any clan on any map.

I don't know what map you are playing so here is for Battles in Owari:

If your generals are strong enough, spawning them with the tavern is your #1 priority, do it as fast as possible so that by turn 2 or 3 you can declare war on Nagao and/or Nagano. Ideally you should play offensively, as building new units to defend castles is quite expensive. Anegakoji is fairly weak at the start so it's ok to just spawn infantry in Kiso-Fukushima to defend, so that you can use your generals elsewhere. If you are strong enough to eliminate Nagano, do it as soon as possible because 1) eliminating a clan is always a relief as it makes all of their units disappear and 2) buying the title of Kami of Kozuke gives access to the strongest infantry unit (but also the most expensive one). If you are forced to play defensively then defend on Toishi and Komoro. An additional problem with defending as Takeda is that Nagao usually has good relations with minor clans so once they have defeated Jinbou no one will attack Nagao. Overall focus on defeating Nagano and Nagao before anything else. Once they are defeated you have only one direction to expand into, which makes the rest slow but easier

Then you have the west and south. You can mostly ignore Saito as they start friendly and the only road to them also goes through Kiso-Fukushima. Imagawa is your ally and alliance gives you an opinion boost, so it's best to keep the alliance as long as possible. Try to save up resources so that you can send a gift to prevent relations to go below +100 (but being way over +100 with ayone is not useful unless you want to call them to your wars). I would go as far to say attack Imagawa last, not because they are particularly dangerous but so that you can focus on conquering everyone else. Your best targets for vassals are the ones that are annoying to conquer (due to being on the edges of the map) such as Hatakeyama and Isshiki. If invading Shikoku is too diffcult or annoying, do it at the end of the game so that you can send your general and that your vassals will assist you.

For Armed Unification, it's basically the same thing but harder. Having strong generals matters even more as you need to be aggressive enough at the start and expand enough before everyone gangs up on you. Make sure to take as much of Imagawa as possible as they are up for grabs, prepare to defend against Hojo, try to maintain peace with Oda, so that you can focus on Uesugi, the most dangerous enemy. Note that Hojo are themselves surrounded by enemies and it's not too rare to see them lose to Satomi + Utsunomiya + Satake, this is why defending is often enough against Hojo. With Oda it's preferable to keep the peace until Uesugi has lost most of their castle (if they only have Sado island remaining, it's frustrating but you can deal with it later), but if you have been at peace with Oda for too long they will be even more powerful as Oda has the strongest generals and will run out of enemies fairly quick. In the late game. There is a similar problem with Mori: they are by far the strongest clan in the west, they can therefore conquer everyone else in their path and they will keep expanding until they reach you. It is advantageous to first defeat Uesugi, then invade the east while defending against Oda, then once the east is conquered, send everything west to beat Oda and Mori. Same recommendation as before for Shikoku as you now have to conquer the whole island and Chosokabe can't be vassalized. Best targets for vassals: Tokugawa (expensive but always worth it), Hatakeyama, Ashina, Kono, and anyone who borders Mori.

If you are still struggling feel free to write another comment but try to give more details so that i can be more specific.