Yes, you can use the past progressive/continuous or past simple tense to make a request or suggestion sound more polite, for example, you can say "I was wondering/I wondered if you could comment on my blog", instead of saying "You should try to comment on my blog".
In addition to 'I was wondering/I wondered', you could use 'I was hoping', 'I was thinking' or 'I thought' instead of 'I hope' or 'I think' to express politeness. That is to say, the past simple or progressive tense can have present or future meaning - to make a request sound 'indirect', 'tentative' or less definite.
Sure, there are other ways to express your politeness. You could use the present progressive or the future tense or some of the modals instead, for example, "I'm hoping you can read my blog" or "I'm looking forward to reading your comment soon" or "I'll have to suggest you proofread your blog before you publish it" or "I would say you'd prepare for another blog challenge - I'm sure Expector's got something up his sleeve".
However, you might enjoy something 'straightforward' or 'direct' if you are outspoken:)
'modal': a word such as 'can', 'may', 'must'
'have something up your sleeve': have a good plan or idea you intend to use later
Comments
Useful tips. Thanks Smith for sharing it.
Thanks, Luci, setareh, bet!
Great!
Dear Expector, Nice tip, Thanks for sharing.
Many thanks, Onee, Mishaikh, dara, Shadow, Shoba!
I wonder if you could help (to) read and comment on the blogs published here, especially those newly posted - I know it takes a lot of time and effort to do that. (Yes, conditionals can be used to make a request sound more polite, too.)
I was wondering if you could take a look at my project work.
I was hoping you would drop me at my place.
I was thinking you would help me to choose the right color.
I am hoping my sentences are polite, dear Sir Expector.
Xie xie admin Smith! Nice blog!
http://www.myenglishclub.com/profiles/blogs/misery-of-a-lover
Expector please check for the mistakes. I would appreciate corrections.