What you might do to remember how many surah you have read or how many rakat you have done is put small shreds of paper, coins, pepples, anything tiny that you can move easily, in front of you to one side when you pray. Put as many out that you need for that prayer, no more, no less. When you finish a surah, for example, if that is what you are missing track of, move a piece of paper/coin/pebble/whatever you chose to the other side. That way you can easily see how many you have done, and how many you need to do still.
Note please that I do not recommend this as an innovation or regular addition to salah, but just as an aide until you are able to keep track on your own, insha'Allah. And remember, what you do out of honest error in prayer, Allah will not hold you accountable for. And Allah loves you for your struggles in becoming closer to Him. Remember what was said about those who struggle reading the Qur'an:
But for those who struggle with reciting the Qur’an they will recieve double the reward of a minimum of 1400 good deeds for each letter:
Aa’ishah (RA), relates that the Prophet (sallAllahu ‘alaihi wa sallam) said:
Verily the one who recites the Qur’an beautifully, smoothly, and precisely, he will be in the company of the noble and obedient angels. And as for the one who recites with difficulty, stammering or stumbling through its verses, then he will have TWICE that reward.” [Al-Bukhari and Muslim]
I was unable to find a hadith that answered struggles with salah, but it is a struggle for you, your own little personal jihad. And the best deeds are praying in its proper time, good treatment of one's parents, and struggling in the name of Allah.
Be strong in this struggle, and insha'Allah with repetition and faith in Allah and yourself that you can do it correctly, the struggle will be lifted.