I made a set of cards with Chinese symbols on one side and the Pinyin and English on the other side (look at the symbol and recall the Pinyin/English, or do it the other way round). I also have printouts with lots of Chinese phrases, to practice translating. I have spreadsheets which generate random numbers and dates for me to practice translating. I still find it difficult to get stuff to 'stick' in my mind. Any other tips and suggestions to help remember and improve my Chinese would be very welcome! Cheers...

From your technique, it seems like you're only concerned about reading and speaking, but not writing. Is that correct? I'd suggest you visit Chinese places such as restaurants and tea houses. If you eat at Chinese restaurant, practice by ordering in Mandarin. Some restaurants have Chinese and English printed on the menus. That would be a good way to check to see if your translations were correct. You could also watch Chinese shows or movies. Personally, I think the best way to learn Mandarin is to find someone who will practice speaking with you. That way they could also correct your pronunciations. Hope this helps.

eat out a lot and practice with chop sticks ;-)

start by eating only Chinese food for six years