The only thing to bear in mind that the week of the wedding you will probably be nervous and stressed.
If you do any of the big things yourself, ie, cake, flowers, venue decoration, catering, most of this needs to be done in this week or in the last few days. Yes you save money but it is potentially opening up yourself to logistical headaches and stress right up to the last minute.
I was so stressed on my wedding morning I couldn't even get my contacts in. I was so glad I opted for a make up and hair artist as no way I could have done my own well with the nerves. Even though it was a lit of money. I am normally cool as a cucumber btw. Never get stressed or nervous about anything!
We also did the cake ourselves. We didn't factor in the heat and a lot of our essentials melted 2 day before. We had to buy double of lots of elements. Would have been cheaper just to buy a professional one.
You forget that professionals know the right ways of doing things and have things like refrigerated vans!
Elements of the wedding are super expensive I know but what I realised post event is that you are buying a 'service' as opposed to just a load of flowers or just a cake.
Balloons are also one to watch- they wilt in the heat and need to be done the day of really.
You will need a team of people to help do things yourself if you plan this at all. What we found was that people were super keen until they realised they were needed on the morning of the wedding and at that point they said 'but when am I going to get ready!'.