One way I like to keep tabs on what God is doing in my life is to keep a journal. I've done this in a number of ways, write on a calendar, a notebook, or on a blog :) I also have a friend that writes down his answered prayers on a stone like in Joshua 4. It is important to remember what God has done - it builds my faith to see how God has moved in response to my prayers.
Joshua 4:1 When all the nation had finished passing over the Jordan, the Lord said to Joshua, 2 “Take twelve men from the people, from each tribe a man, 3 and command them, saying, ‘Take twelve stones from here out of the midst of the Jordan, from the very place where the priests' feet stood firmly, and bring them over with you and lay them down in the place where you lodge tonight.’” 4 Then Joshua called the twelve men from the people of Israel, whom he had appointed, a man from each tribe. 5 And Joshua said to them, “Pass on before the ark of the Lord your God into the midst of the Jordan, and take up each of you a stone upon his shoulder, according to the number of the tribes of the people of Israel, 6 that this may be a sign among you. When your children ask in time to come, ‘What do those stones mean to you?’ 7 then you shall tell them that the waters of the Jordan were cut off before the ark of the covenant of the Lord. When it passed over the Jordan, the waters of the Jordan were cut off. So these stones shall be to the people of Israel a memorial forever.”