As some one who takes great meticulous care in planning and investing regularly, both for the long term and super long term(retirement savings), I can pitch in and offer some advice here.
First advice I would give is, totally avoid using credit cards. It might sound impractical, but I've found some workarounds for it. Which is to use my debit card as a credit card. Go frugal for a few days and save some money in the savings account, then use that money as credit to yourself. The worst thing about any kind of debt/loan is the interest part. Lesser interest you pay the better, except in situation where you are making an investment with the loan(like buying a property of a home) and the value of the investment is growing faster, when the at the same time inflation is decreasing your loan's net value.
Second advice I can give you is to buy your own home and avoid paying rent. If you look at the whole thing having your own home is vastly more profitable than renting some one else's home on a long term.
Then there are a few assorted advices I would like to give, especially to people in India(My country), But I believe it applies equally to else where to. Buy gold in small quantities regularly. Gold is protected from inflation, and is the near standard of economic growth around the world. And value of growth(over long term) always grows. Once you have sufficient gold- sell it and, learn to buy real estate in city outskirts. You will see in any growing city, sooner or later outskirts merge into main city areas and then real estate prices shoot up. Take loans to do this, if and only if the loan is small and as I said before, inflation affects your loan faster than, the rate at which its value grows.
Make the mandatory 1 lac per year(if you can't make as much as you can), tax savings investments on things like endowment insurances which serve as both life insurance and long term investments.
Its good if you could rotate money by building a home which you could rent out. It will serve as a steady source of income later and after retirement.
Lastly at the risk of attracting downvotes, please don't invest in stocks and show pointless heroics if you don't understand that business. Far more people have burnt their hard savings hoping for magical miracles to happen and make them millionaire while dealing in stocks. In short if you know how to do it, do it. Else keep out for your own good.