If you find yourself forgetting all your french, like me, and need some help when writing, here are a few useful tools.
The first is a linguistic dictionary/database that is offered by the Canadian Translation Bureau: Termium. This dictionary can actually be used for English, French and Spanish translation and definitions. It accesses a database with all the different uses of the word so you can find the one that best suits your needs. To use it, you choose what language you are searching in, English, French, Spanish, or all three under the Search Keys button, and then type a word to see the definition and translations.
There is also a handy tool called BonPatron that corrects French spelling and usage. It doesn't help with verb tenses or whether to use avoir or être in past participles like that, but it will catch noun endings and accent use, etc. I find it helpful since I can't seem to remember word genders.
And, of course, you can always consult English-French or monolingual dictionaries and the very helpful Bescherelle for French verbs (la conjugaison).